Vaccination against COVID-19 - risks and benefits in children

Countries in Europe and around the world have taken varying approaches to their policies on COVID-19 vaccination for children. The low risk of severe illness from COVID-19 means that even small risks from vaccination warrant careful consideration. Vaccination appears to result in a decreased risk of severe illness including the paediatric multi-system inflammatory syndrome known to be associated with COVID-19. These risks have already decreased significantly with the emergence of the Omicron variant and its subvariants, and due to widespread population immunity through previous infection. There is a relatively high risk of myocarditis following second doses of mRNA vaccines in adolescent males, although the general course of this condition appears mild.   Conclusion: COVID-19 vaccination only provides a transient reduction in transmission. Currently, insufficient evidence exists to determine the impact of vaccination on post-acute COVID syndromes in children, which are uncommon. What is Known: • Vaccines against COVID-19 have significantly reduced morbidity and mortality around the world. • Whilst countries have universally recommended vaccines for adults and continue to recommend them for vulnerable populations, there has been more variability in recommendations for children. What is New: • In the setting of near universal existing immunity from infection, the majority of the initial benefit in protecting against severe illness has been eroded. • The risks of myocarditis following mRNA vaccination for children is low, but an important consideration given the modest benefits.

Oral Valganciclovir Initiated Beyond 1 Month of Age as Treatment of Sensorineural Hearing Loss Caused by Congenital Cytomegalovirus Infection: A Randomized Clinical Trial

OBJECTIVE

The objective of this study was to determine if valganciclovir initiated after 1 month of age improves congenital cytomegalovirus-associated sensorineural hearing loss.

STUDY DESIGN

We conducted a randomized, double-blind, placebo-controlled phase 2 trial of 6 weeks of oral valganciclovir at US (n = 12) and UK (n = 9) sites. Patients of ages 1 month through 3 years with baseline sensorineural hearing loss were enrolled. The primary outcome was change in total ear hearing between baseline and study month 6. Secondary outcome measures included change in best ear hearing and reduction in cytomegalovirus viral load in blood, saliva, and urine.

RESULTS

Of 54 participants enrolled, 35 were documented to have congenital cytomegalovirus infection and were randomized (active group: 17; placebo group: 18). Mean age at enrollment was 17.8 ± 15.8 months (valganciclovir) vs 19.5 ± 13.1 months (placebo). Twenty (76.9%) of the 26 ears from subjects in the active treatment group did not have worsening of hearing, compared with 27 (96.4%) of 28 ears from subjects in the placebo group (P = .09). All other comparisons of total ear or best ear hearing outcomes were also not statistically significant. Saliva and urine viral loads decreased significantly in the valganciclovir group but did not correlate with change in hearing outcome.

CONCLUSIONS

In this randomized controlled trial, initiation of antiviral therapy beyond the first month of age did not improve hearing outcomes in children with congenital cytomegalovirus-associated sensorineural hearing loss.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov identifier NCT01649869.

Dimethyl fumarate in patients admitted to hospital with COVID-19 (RECOVERY): a randomised, controlled, open-label, platform trial

Dimethyl fumarate (DMF) inhibits inflammasome-mediated inflammation and has been proposed as a treatment for patients hospitalised with COVID-19. This randomised, controlled, open-label platform trial (Randomised Evaluation of COVID-19 Therapy [RECOVERY]), is assessing multiple treatments in patients hospitalised for COVID-19 (NCT04381936, ISRCTN50189673). In this assessment of DMF performed at 27 UK hospitals, adults were randomly allocated (1:1) to either usual standard of care alone or usual standard of care plus DMF. The primary outcome was clinical status on day 5 measured on a seven-point ordinal scale. Secondary outcomes were time to sustained improvement in clinical status, time to discharge, day 5 peripheral blood oxygenation, day 5 C-reactive protein, and improvement in day 10 clinical status. Between 2 March 2021 and 18 November 2021, 713 patients were enroled in the DMF evaluation, of whom 356 were randomly allocated to receive usual care plus DMF, and 357 to usual care alone. 95% of patients received corticosteroids as part of routine care. There was no evidence of a beneficial effect of DMF on clinical status at day 5 (common odds ratio of unfavourable outcome 1.12; 95% CI 0.86-1.47; p = 0.40). There was no significant effect of DMF on any secondary outcome.

Safety and Immunogenicity of a ChAd155-Vectored Respiratory Syncytial Virus Vaccine in Infants 6-7 Months of age: A Phase 1/2 Randomized Trial

BACKGROUND

Respiratory syncytial virus (RSV) is a common cause of lower respiratory tract infections in infants. This phase 1/2, observer-blind, randomized, controlled study assessed the safety and immunogenicity of an investigational chimpanzee-derived adenoviral vector RSV vaccine (ChAd155-RSV, expressing RSV F, N, and M2-1) in infants.

METHODS

Healthy 6- to 7-month-olds were 1:1:1-randomized to receive 1 low ChAd155-RSV dose (1.5 × 1010 viral particles) followed by placebo (RSV_1D); 2 high ChAd155-RSV doses (5 × 1010 viral particles) (RSV_2D); or active comparator vaccines/placebo (comparator) on days 1 and 31. Follow-up lasted approximately 2 years.

RESULTS

Two hundred one infants were vaccinated (RSV_1D: 65; RSV_2D: 71; comparator: 65); 159 were RSV-seronaive at baseline. Most solicited and unsolicited adverse events after ChAd155-RSV occurred at similar or lower rates than after active comparators. In infants who developed RSV infection, there was no evidence of vaccine-associated enhanced respiratory disease (VAERD). RSV-A neutralizing titers and RSV F-binding antibody concentrations were higher post-ChAd155-RSV than postcomparator at days 31, 61, and end of RSV season 1 (mean follow-up, 7 months). High-dose ChAd155-RSV induced stronger responses than low-dose, with further increases post-dose 2.

CONCLUSIONS

ChAd155-RSV administered to 6- to 7-month-olds had a reactogenicity/safety profile like other childhood vaccines, showed no evidence of VAERD, and induced a humoral immune response. Clinical Trials Registration. NCT03636906.

Nirsevimab for Prevention of Hospitalizations Due to RSV in Infants

BACKGROUND

The safety of the monoclonal antibody nirsevimab and the effect of nirsevimab on hospitalizations for respiratory syncytial virus (RSV)-associated lower respiratory tract infection when administered in healthy infants are unclear.

METHODS

In a pragmatic trial, we randomly assigned, in a 1:1 ratio, infants who were 12 months of age or younger, had been born at a gestational age of at least 29 weeks, and were entering their first RSV season in France, Germany, or the United Kingdom to receive either a single intramuscular injection of nirsevimab or standard care (no intervention) before or during the RSV season. The primary end point was hospitalization for RSV-associated lower respiratory tract infection, defined as hospital admission and an RSV-positive test result. A key secondary end point was very severe RSV-associated lower respiratory tract infection, defined as hospitalization for RSV-associated lower respiratory tract infection with an oxygen saturation of less than 90% and the need for supplemental oxygen.

RESULTS

A total of 8058 infants were randomly assigned to receive nirsevimab (4037 infants) or standard care (4021 infants). Eleven infants (0.3%) in the nirsevimab group and 60 (1.5%) in the standard-care group were hospitalized for RSV-associated lower respiratory tract infection, which corresponded to a nirsevimab efficacy of 83.2% (95% confidence interval [CI], 67.8 to 92.0; P<0.001). Very severe RSV-associated lower respiratory tract infection occurred in 5 infants (0.1%) in the nirsevimab group and in 19 (0.5%) in the standard-care group, which represented a nirsevimab efficacy of 75.7% (95% CI, 32.8 to 92.9; P = 0.004). The efficacy of nirsevimab against hospitalization for RSV-associated lower respiratory tract infection was 89.6% (adjusted 95% CI, 58.8 to 98.7; multiplicity-adjusted P<0.001) in France, 74.2% (adjusted 95% CI, 27.9 to 92.5; multiplicity-adjusted P = 0.006) in Germany, and 83.4% (adjusted 95% CI, 34.3 to 97.6; multiplicity-adjusted P = 0.003) in the United Kingdom. Treatment-related adverse events occurred in 86 infants (2.1%) in the nirsevimab group.

CONCLUSIONS

Nirsevimab protected infants against hospitalization for RSV-associated lower respiratory tract infection and against very severe RSV-associated lower respiratory tract infection in conditions that approximated real-world settings. (Funded by Sanofi and AstraZeneca; HARMONIE ClinicalTrials.gov number, NCT05437510).

Serum HCoV-spike specific antibodies do not protect against subsequent SARS-CoV-2 infection in children and adolescents

SARS-CoV-2 infections in children are generally asymptomatic or mild and rarely progress to severe disease and hospitalization. Why this is so remains unclear. Here we explore the potential for protection due to pre-existing cross-reactive seasonal coronavirus antibodies and compare the rate of antibody decline for nucleocapsid and spike protein in serum and oral fluid against SARS-CoV-2 within the pediatric population. No differences in seasonal coronaviruses antibody concentrations were found at baseline between cases and controls, suggesting no protective effect from pre-existing immunity against seasonal coronaviruses. Antibodies against seasonal betacoronaviruses were boosted in response to SARS-CoV-2 infection. In serum, anti-nucleocapsid antibodies fell below the threshold of positivity more quickly than anti-spike protein antibodies. These findings add to our understanding of protection against infection with SARS-CoV-2 within the pediatric population, which is important when considering pediatric SARS-CoV-2 immunization policies.

The disease burden of respiratory syncytial virus in Infants

PURPOSE OF REVIEW

To describe the current global burden of respiratory syncytial virus (RSV) in infants and its implications for morbidity, health resources and economic costs.

RECENT FINDINGS

New prophylactic therapies are on the horizon for RSV in the form of long-acting monoclonal antibodies suitable for healthy infants and maternal immunizations.

SUMMARY

Despite being responsible for significant global infant morbidity and mortality, until recently there have been no effective therapeutics available for healthy infants to protect them from RSV. Several new drugs are likely to be available within the next few years which could help relieve a huge burden on healthcare systems over the coming winters.

Reactogenicity, immunogenicity and breakthrough infections following heterologous or fractional second dose COVID-19 vaccination in adolescents (Com-COV3): A randomised controlled trial

BACKGROUND

This was the first study to investigate the reactogenicity and immunogenicity of heterologous or fractional second dose COVID-19 vaccine regimens in adolescents.

METHODS

A phase II, single-blind, multi-centre, randomised-controlled trial recruited across seven UK sites from September to November 2021, with follow-up visits to August 2022. Healthy 12-to-16 years olds were randomised (1:1:1) to either 30 µg BNT162b2 (BNT-30), 10 µg BNT162b2 (BNT-10), or NVX-CoV2373 (NVX), 8 weeks after a first 30 µg dose of BNT162b2. The primary outcome was solicited systemic reactions in the week following vaccination. Secondary outcomes included immunogenicity and safety. 'Breakthrough infection' analyses were exploratory.

FINDINGS

148 participants were recruited (median age 14 years old, 62% female, 26% anti-nucleocapsid IgG seropositive pre-second dose); 132 participants received a second dose. Reactions were mostly mild-to-moderate, with lower rates in BNT-10 recipients. No vaccine-related serious adverse events occurred. Compared to BNT-30, at 28 days post-second dose anti-spike antibody responses were similar for NVX (adjusted geometric mean ratio [aGMR]) 1.09 95% confidence interval (CI): 0.84, 1.42] and lower for BNT-10 (aGMR 0.78 [95% CI: 0.61, 0.99]). For Omicron BA.1 and BA.2, the neutralising antibody titres for BNT-30 at day 28 were similar for BNT-10 (aGMR 1.0 [95% CI: 0.65, 1.54] and 1.02 [95% CI: 0.71, 1.48], respectively), but higher for NVX (aGMR 1.7 [95% CI: 1.07, 2.69] and 1.43 [95% CI: 0.96, 2.12], respectively). Compared to BNT-30, cellular immune responses were greatest for NVX (aGMR 1.73 [95% CI: 0.94, 3.18]), and lowest for BNT-10 (aGMR 0.65 [95% CI: 0.37, 1.15]) at 14 days post-second dose. Cellular responses were similar across the study arms by day 236 post-second dose. Amongst SARS-CoV-2 infection naïve participants, NVX participants had an 89% reduction in risk of self-reported 'breakthrough infection' compared to BNT-30 (adjusted hazard ratio [aHR] 0.11 [95% CI: 0.01, 0.86]) up until day 132 after second dose. BNT-10 recipients were more likely to have a 'breakthrough infection' compared to BNT-30 (aHR 2.14 [95% CI: 1.02, 4.51]) up to day 132 and day 236 post-second dose. Antibody responses at 132 and 236 days after second dose were similar for all vaccine schedules.

INTERPRETATION

Heterologous and fractional dose COVID-19 vaccine schedules in adolescents are safe, well-tolerated and immunogenic. The enhanced performance of the heterologous schedule using NVX-CoV2373 against the Omicron SARS-CoV-2 variant suggests this mRNA prime and protein-subunit boost schedule may provide a greater breadth of protection than the licensed homologous schedule.

FUNDING

National Institute for Health Research and Vaccine Task Force.

TRIAL REGISTRATION

International Standard Randomised Controlled Trial Number registry: 12348322.

Persistence of immune responses after heterologous and homologous third COVID-19 vaccine dose schedules in the UK: eight-month analyses of the COV-BOOST trial

BACKGROUND

COV-BOOST is a multicentre, randomised, controlled, phase 2 trial of seven COVID-19 vaccines used as a third booster dose in June 2021. Monovalent messenger RNA (mRNA) COVID-19 vaccines were subsequently widely used for the third and fourth-dose vaccination campaigns in high-income countries. Real-world vaccine effectiveness against symptomatic infections following third doses declined during the Omicron wave. This report compares the immunogenicity and kinetics of responses to third doses of vaccines from day (D) 28 to D242 following third doses in seven study arms.

METHODS

The trial initially included ten experimental vaccine arms (seven full-dose, three half-dose) delivered at three groups of six sites. Participants in each site group were randomised to three or four experimental vaccines, or MenACWY control. The trial was stratified such that half of participants had previously received two primary doses of ChAdOx1 nCov-19 (Oxford-AstraZeneca; hereafter referred to as ChAd) and half had received two doses of BNT162b2 (Pfizer-BioNtech, hereafter referred to as BNT). The D242 follow-up was done in seven arms (five full-dose, two half-dose). The BNT vaccine was used as the reference as it was the most commonly deployed third-dose vaccine in clinical practice in high-income countries. The primary analysis was conducted using all randomised and baseline seronegative participants who were SARS-CoV-2 naïve during the study and who had not received a further COVID-19 vaccine for any reason since third dose randomisation.

RESULTS

Among the 817 participants included in this report, the median age was 72 years (IQR: 55-78) with 50.7% being female. The decay rates of anti-spike IgG between vaccines are different among both populations who received initial doses of ChAd/ChAd and BNT/BNT. In the population that previously received ChAd/ChAd, mRNA vaccines had the highest titre at D242 following their vaccine dose although Ad26. COV2. S (Janssen; hereafter referred to as Ad26) showed slower decay. For people who received BNT/BNT as their initial doses, a slower decay was also seen in the Ad26 and ChAd arms. The anti-spike IgG became significantly higher in the Ad26 arm compared to the BNT arm as early as 3 months following vaccination. Similar decay rates were seen between BNT and half-BNT; the geometric mean ratios ranged from 0.76 to 0.94 at different time points. The difference in decay rates between vaccines was similar for wild-type live virus-neutralising antibodies and that seen for anti-spike IgG. For cellular responses, the persistence was similar between study arms.

CONCLUSIONS

Heterologous third doses with viral vector vaccines following two doses of mRNA achieve more durable humoral responses compared with three doses of mRNA vaccines. Lower doses of mRNA vaccines could be considered for future booster campaigns.

Antibiotics for lower respiratory tract infection in children presenting in primary care: ARTIC-PC RCT

Background

Antimicrobial resistance is a global health threat. Antibiotics are commonly prescribed for children with uncomplicated lower respiratory tract infections, but there is little randomised evidence to support the effectiveness of antibiotics in treating these infections, either overall or relating to key clinical subgroups in which antibiotic prescribing is common (chest signs; fever; physician rating of unwell; sputum/rattly chest; shortness of breath).

Objectives

To estimate the clinical effectiveness and cost-effectiveness of amoxicillin for uncomplicated lower respiratory tract infections in children both overall and in clinical subgroups.

Design

Placebo-controlled trial with qualitative, observational and cost-effectiveness studies.

Setting

UK general practices.

Participants

Children aged 1-12 years with acute uncomplicated lower respiratory tract infections.

Outcomes

The primary outcome was the duration in days of symptoms rated moderately bad or worse (measured using a validated diary). Secondary outcomes were symptom severity on days 2-4 (0 = no problem to 6 = as bad as it could be); symptom duration until very little/no problem; reconsultations for new or worsening symptoms; complications; side effects; and resource use.

Methods

Children were randomised to receive 50 mg/kg/day of oral amoxicillin in divided doses for 7 days, or placebo using pre-prepared packs, using computer-generated random numbers by an independent statistician. Children who were not randomised could participate in a parallel observational study. Semistructured telephone interviews explored the views of 16 parents and 14 clinicians, and the data were analysed using thematic analysis. Throat swabs were analysed using multiplex polymerase chain reaction.

Results

A total of 432 children were randomised (antibiotics, n = 221; placebo, n = 211). The primary analysis imputed missing data for 115 children. The duration of moderately bad symptoms was similar in the antibiotic and placebo groups overall (median of 5 and 6 days, respectively; hazard ratio 1.13, 95% confidence interval 0.90 to 1.42), with similar results for subgroups, and when including antibiotic prescription data from the 326 children in the observational study. Reconsultations for new or worsening symptoms (29.7% and 38.2%, respectively; risk ratio 0.80, 95% confidence interval 0.58 to 1.05), illness progression requiring hospital assessment or admission (2.4% vs. 2.0%) and side effects (38% vs. 34%) were similar in the two groups. Complete-case (n = 317) and per-protocol (n = 185) analyses were similar, and the presence of bacteria did not mediate antibiotic effectiveness. NHS costs per child were slightly higher (antibiotics, £29; placebo, £26), with no difference in non-NHS costs (antibiotics, £33; placebo, £33). A model predicting complications (with seven variables: baseline severity, difference in respiratory rate from normal for age, duration of prior illness, oxygen saturation, sputum/rattly chest, passing urine less often, and diarrhoea) had good discrimination (bootstrapped area under the receiver operator curve 0.83) and calibration. Parents found it difficult to interpret symptoms and signs, used the sounds of the child's cough to judge the severity of illness, and commonly consulted to receive a clinical examination and reassurance. Parents acknowledged that antibiotics should be used only when 'necessary', and clinicians noted a reduction in parents' expectations for antibiotics.

Limitations

The study was underpowered to detect small benefits in key subgroups.

Conclusion

Amoxicillin for uncomplicated lower respiratory tract infections in children is unlikely to be clinically effective or to reduce health or societal costs. Parents need better access to information, as well as clear communication about the self-management of their child's illness and safety-netting.

Future work

The data can be incorporated in the Cochrane review and individual patient data meta-analysis.

Trial registration

This trial is registered as ISRCTN79914298.

Funding

This project was funded by the National Institute for Health and Care Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 27, No. 9. See the NIHR Journals Library website for further project information.

Persistence of immune response in heterologous COVID vaccination schedules in the Com-COV2 study - A single-blind, randomised trial incorporating mRNA, viral-vector and protein-adjuvant vaccines

BACKGROUND

Heterologous COVID vaccine priming schedules are immunogenic and effective. This report aims to understand the persistence of immune response to the viral vectored, mRNA and protein-based COVID-19 vaccine platforms used in homologous and heterologous priming combinations, which will inform the choice of vaccine platform in future vaccine development.

METHODS

Com-COV2 was a single-blinded trial in which adults ≥ 50 years, previously immunised with single dose 'ChAd' (ChAdOx1 nCoV-19, AZD1222, Vaxzevria, Astrazeneca) or 'BNT' (BNT162b2, tozinameran, Comirnaty, Pfizer/BioNTech), were randomised 1:1:1 to receive a second dose 8-12 weeks later with either the homologous vaccine, or 'Mod' (mRNA-1273, Spikevax, Moderna) or 'NVX' (NVX-CoV2373, Nuvaxovid, Novavax). Immunological follow-up and the secondary objective of safety monitoring were performed over nine months. Analyses of antibody and cellular assays were performed on an intention-to-treat population without evidence of COVID-19 infection at baseline or for the trial duration.

FINDINGS

In April/May 2021, 1072 participants were enrolled at a median of 9.4 weeks after receipt of a single dose of ChAd (N = 540, 45% female) or BNT (N = 532, 39% female) as part of the national vaccination programme. In ChAd-primed participants, ChAd/Mod had the highest anti-spike IgG from day 28 through to 6 months, although the heterologous vs homologous geometric mean ratio (GMR) dropped from 9.7 (95% CI (confidence interval): 8.2, 11.5) at D28 to 6.2 (95% CI: 5.0, 7.7) at D196. The heterologous/homologous GMR for ChAd/NVX similarly dropped from 3.0 (95% CI:2.5,3.5) to 2.4 (95% CI:1.9, 3.0). In BNT-primed participants, decay was similar between heterologous and homologous schedules with BNT/Mod inducing the highest anti-spike IgG for the duration of follow-up. The adjusted GMR (aGMR) for BNT/Mod compared with BNT/BNT increased from 1.36 (95% CI: 1.17, 1.58) at D28 to 1.52 (95% CI: 1.21, 1.90) at D196, whilst for BNT/NVX this aGMR was 0.55 (95% CI: 0.47, 0.64) at day 28 and 0.62 (95% CI: 0.49, 0.78) at day 196. Heterologous ChAd-primed schedules produced and maintained the largest T-cell responses until D196. Immunisation with BNT/NVX generated a qualitatively different antibody response to BNT/BNT, with the total IgG significantly lower than BNT/BNT during all follow-up time points, but similar levels of neutralising antibodies.

INTERPRETATION

Heterologous ChAd-primed schedules remain more immunogenic over time in comparison to ChAd/ChAd. BNT-primed schedules with a second dose of either mRNA vaccine also remain more immunogenic over time in comparison to BNT/NVX. The emerging data on mixed schedules using the novel vaccine platforms deployed in the COVID-19 pandemic, suggest that heterologous priming schedules might be considered as a viable option sooner in future pandemics.

ISRCTN

27841311 EudraCT:2021-001275-16.

Persistence of the immune response after two doses of ChAdOx1 nCov-19 (AZD1222): 1 year of follow-up of two randomized controlled trials

The trajectory of immune responses following the primary dose series determines the decline in vaccine effectiveness over time. Here we report on maintenance of immune responses during the year following a two-dose schedule of ChAdOx1 nCoV-19/AZD1222, in the absence of infection, and also explore the decay of antibody after infection. Total spike-specific IgG antibody titres were lower with two low doses of ChAdOx1 nCoV-19 vaccines (two low doses) (P = 0.0006) than with 2 standard doses (the approved dose) or low dose followed by standard dose vaccines regimens. Longer intervals between first and second doses resulted in higher antibody titres (P < 0.0001); however, there was no evidence that the trajectory of antibody decay differed by interval or by vaccine dose, and the decay of IgG antibody titres followed a similar trajectory after a third dose of ChAdOx1 nCoV-19. Trends in post-infection samples were similar with an initial rapid decay in responses but good persistence of measurable responses thereafter. Extrapolation of antibody data, following two doses of ChAdOx1 nCov-19, demonstrates a slow rate of antibody decay with modelling, suggesting that antibody titres are well maintained for at least 2 years. These data suggest a persistent immune response after two doses of ChAdOx1 nCov-19 which will likely have a positive impact against serious disease and hospitalization.

Psychological distress experienced by parents caring for an immunosuppressed child during the COVID-19 pandemic

The COVID-19 pandemic has proved unique in both its unpredictability and the extent to which it has continued to impact on daily life since March 2020. Among the immunosuppressed population the challenges of the COVID-19 pandemic are cumulative to the ever-present challenges of living with a long-term condition. This prospective longitudinal study explored patterns of concern experienced by 467 British parents caring for an immunosuppressed child during the first 2 years of the COVID-19 pandemic and related this to parental mental wellbeing. Most parents slowly adapted or were resilient to the ever-changing stressors of the COVID-19 pandemic. However, 12% experienced high levels of concern throughout the first 2 years of the pandemic. This group was also more likely to report emotional mental health problems towards the end of this period. The experience of emotional mental health problems among parents caring for an immunosuppressed child was related to low household income, single parenting, difficult access to greenspace, and higher level of exposure to COVID positive cases and COVID restrictions (North of England). Parents reported that optimism, reduction of isolation, and support promoted coping and management of the challenges of the COVID-19 pandemic. More reliable COVID information and periodic medical-condition-specific guidance would have been appreciated. These findings can increase clinical awareness of high-risk parental groups and make an important contribution to the planning of appropriate targeted psychological family interventions.

Comparative genomic epidemiology of serotype 3 IPD and carriage isolates from Southampton, UK between 2005 and 2017

Serotype 3 pneumococci remains a significant cause of disease despite its inclusion in PCV13. Whilst clonal complex 180 (CC180) represents the major clone, recent studies have refined the population structure into three clades: Iα, Iβ and II, with the last being a recent divergent and more antibiotic-resistant. We present a genomic analysis of serotype 3 isolates from paediatric carriage and all-age invasive disease, collected between 2005 and 2017 in Southampton, UK. Forty-one isolates were available for analysis. Eighteen were isolated during the annual cross-sectional surveillance of paediatric pneumococcal carriage. The remaining 23 were isolated from blood/cerebrospinal fluid specimens at the University Hospital Southampton NHS Foundation Trust laboratory. All carriage isolates were CC180 GPSC12. Greater diversity was seen with invasive pneumococcal disease (IPD) with three GPSC83 (ST1377: n=2, ST260: n=1) and one GPSC3 (ST1716). For both carriage and IPD, Clade Iα was dominant (94.4 and 73.9 % respectively). Two isolates were Clade II with one from carriage (a 34-month-old, October 2017) and one invasive isolate (49-year-old, August 2015). Four IPD isolates were outside the CC180 clade. All isolates were genotypically susceptible to penicillin, erythromycin, tetracycline, co-trimoxazole and chloramphenicol. Two isolates (one each from carriage and IPD; both CC180 GPSC12) were phenotypically resistant to erythromycin and tetracycline; the IPD isolate was also resistant to oxacillin.In the Southampton area, carriage and invasive disease associated with serotype 3 is predominantly caused by Clade Iα CC180 GPSC12.

Diagnosing acute bone and joint infection in children

Acute bone and joint infections in children are serious, and misdiagnosis can threaten limb and life. Most young children who present acutely with pain, limping, and/or loss of function have transient synovitis, which will resolve spontaneously within a few days. A minority will have a bone or joint infection. Clinicians are faced with a diagnostic challenge: children with transient synovitis can safely be sent home, but children with bone and joint infection require urgent treatment to avoid complications. Clinicians often respond to this challenge by using a series of rudimentary decision support tools, based on clinical, haematological, and biochemical parameters, to differentiate childhood osteoarticular infection from other diagnoses. However, these tools were developed without methodological expertise in diagnostic accuracy and do not consider the importance of imaging (ultrasound scan and MRI). There is wide variation in clinical practice with regard to the indications, choice, sequence, and timing of imaging. This variation is most likely due to the lack of evidence concerning the role of imaging in acute bone and joint infection in children. We describe the first steps of a large UK multicentre study, funded by the National Institute for Health Research, which seeks to integrate definitively the role of imaging into a decision support tool, developed with the assistance of individuals with expertise in the development of clinical prediction tools.

COVAC1 phase 2a expanded safety and immunogenicity study of a self-amplifying RNA vaccine against SARS-CoV-2

Background

Lipid nanoparticle (LNP) encapsulated self-amplifying RNA (saRNA) is well tolerated and immunogenic in SARS-CoV-2 seronegative and seropositive individuals aged 18-75.

Methods

A phase 2a expanded safety and immunogenicity study of a saRNA SARS-CoV-2 vaccine candidate LNP-nCoVsaRNA, was conducted at participating centres in the UK between 10th August 2020 and 30th July 2021. Participants received 1 μg then 10 μg of LNP-nCoVsaRNA, ∼14 weeks apart. Solicited adverse events (AEs) were collected for one week post-each vaccine, and unsolicited AEs throughout. Binding and neutralisating anti-SARS-CoV-2 antibody raised in participant sera was measured by means of an anti-Spike (S) IgG ELISA, and SARS-CoV-2 pseudoneutralisation assay. (The trial is registered: ISRCTN17072692, EudraCT 2020-001646-20).

Findings

216 healthy individuals (median age 51 years) received 1.0 μg followed by 10.0 μg of the vaccine. 28/216 participants were either known to have previous SARS-CoV2 infection and/or were positive for anti-Spike (S) IgG at baseline. Reactogenicity was as expected based on the reactions following licensed COVID-19 vaccines, and there were no serious AEs related to vaccination. 80% of baseline SARS-CoV-2 naïve individuals (147/183) seroconverted two weeks post second immunization, irrespective of age (18-75); 56% (102/183) had detectable neutralising antibodies. Almost all (28/31) SARS-CoV-2 positive individuals had increased S IgG binding antibodies following their first 1.0 μg dose with a ≥0.5log10 increase in 71% (22/31).

Interpretation

Encapsulated saRNA was well tolerated and immunogenic in adults aged 18-75 years. Seroconversion rates in antigen naïve were higher than those reported in our dose-ranging study. Further work is required to determine if this difference is related to a longer dosing interval (14 vs. 4 weeks) or dosing with 1.0 μg followed by 10.0 μg. Boosting of S IgG antibodies was observed with a single 1.0 μg injection in those with pre-existing immune responses.

Funding

Grants and gifts from the Medical Research Council UKRI (MC_PC_19076), the National Institute for Health Research/Vaccine Task Force, Partners of Citadel and Citadel Securities, Sir Joseph Hotung Charitable Settlement, Jon Moulton Charity Trust, Pierre Andurand, and Restore the Earth.

Comparison of UK paediatric SARS-CoV-2 admissions across the first and second pandemic waves

BACKGROUND

We hypothesised that the clinical characteristics of hospitalised children and young people (CYP) with SARS-CoV-2 in the UK second wave (W2) would differ from the first wave (W1) due to the alpha variant (B.1.1.7), school reopening and relaxation of shielding.

METHODS

Prospective multicentre observational cohort study of patients <19 years hospitalised in the UK with SARS-CoV-2 between 17/01/20 and 31/01/21. Clinical characteristics were compared between W1 and W2 (W1 = 17/01/20-31/07/20,W2 = 01/08/20-31/01/21).

RESULTS

2044 CYP < 19 years from 187 hospitals. 427/2044 (20.6%) with asymptomatic/incidental SARS-CoV-2 were excluded from main analysis. 16.0% (248/1548) of symptomatic CYP were admitted to critical care and 0.8% (12/1504) died. 5.6% (91/1617) of symptomatic CYP had Multisystem Inflammatory Syndrome in Children (MIS-C). After excluding CYP with MIS-C, patients in W2 had lower Paediatric Early Warning Scores (PEWS, composite vital sign score), lower antibiotic use and less respiratory and cardiovascular support than W1. The proportion of CYP admitted to critical care was unchanged. 58.0% (938/1617) of symptomatic CYP had no reported comorbidity. Patients without co-morbidities were younger (42.4%, 398/938, <1 year), had lower PEWS, shorter length of stay and less respiratory support.

CONCLUSIONS

We found no evidence of increased disease severity in W2 vs W1. A large proportion of hospitalised CYP had no comorbidity.

IMPACT

No evidence of increased severity of COVID-19 admissions amongst children and young people (CYP) in the second vs first wave in the UK, despite changes in variant, relaxation of shielding and return to face-to-face schooling. CYP with no comorbidities made up a significant proportion of those admitted. However, they had shorter length of stays and lower treatment requirements than CYP with comorbidities once those with MIS-C were excluded. At least 20% of CYP admitted in this cohort had asymptomatic/incidental SARS-CoV-2 infection. This paper was presented to SAGE to inform CYP vaccination policy in the UK.

Effect of colonisation with Neisseria lactamica on cross-reactive anti-meningococcal B-cell responses: a randomised, controlled, human infection trial

BACKGROUND

Pharyngeal colonisation by the commensal bacterium Neisseria lactamica inhibits colonisation by Neisseria meningitidis and has an inverse epidemiological association with meningococcal disease. The mechanisms that underpin this relationship are unclear, but could involve the induction of cross-reactive immunity. In this study, we aimed to evaluate whether colonisation with N lactamica induces N lactamica-specific B-cell responses that are cross-reactive with N meningitidis.

METHODS

In this randomised, placebo-controlled, human infection trial at University Hospital Southampton Clinical Research Facility (Southampton, UK), healthy adults aged 18-45 years were randomly assigned (2:1) to receive intranasal inoculation with either 105 colony-forming units of N lactamica in 1 mL phosphate-buffered saline (PBS) or 1 mL PBS alone. Participants and researchers conducting participant sampling and immunological assays were masked to allocation. The primary endpoint was the frequency of circulating N lactamica-specific plasma cells and memory B cells after N lactamica inoculation (day 7-28) compared with baseline values (day 0), measured using enzyme-linked immunospot assays. The secondary endpoint was to measure the frequency of N meningitidis-specific B cells. In a second study, we measured the effect of duration of N lactamica colonisation on seroconversion by terminating carriage at either 4 days or 14 days with single-dose oral ciprofloxacin. The studies are now closed to participants. The trials are registered with ClinicalTrials.gov, NCT03633474 and NCT03549325.

FINDINGS

Of 50 participants assessed for eligibility between Sept 5, 2018, and March 3, 2019, 31 were randomly assigned (n=20 N lactamica, n=11 PBS). Among the 17 participants who were colonised with N lactamica, the median baselines compared with peak post-colonisation N lactamica-specific plasma-cell frequencies (per 105 peripheral blood mononuclear cells) were 0·0 (IQR 0·0-0·0) versus 5·0 (1·5-10·5) for IgA-secreting plasma cells (p<0·0001), and 0·0 (0·0-0·0) versus 3·0 (1·5-9·5) for IgG-secreting plasma cells (p<0·0001). Median N lactamica-specific IgG memory-B-cell frequencies (percentage of total IgG memory B cells) increased from 0·0024% (0·0000-0·0097) at baseline to 0·0384% (0·0275-0·0649) at day 28 (p<0·0001). The frequency of N meningitidis-specific IgA-secreting and IgG-secreting plasma cells and memory B cells also increased signficantly in participants who were colonised with N lactamica. Upper respiratory tract symptoms were reported in ten (50%) of 20 participants who were inoculated with N lactamica and six (55%) of 11 participants who were inoculated with PBS (p>0·99). Three additional adverse events (two in the N lactamica group and one in the PBS group) and no serious adverse events were reported. In the second study, anti-N lactamica and anti-N meningitidis serum IgG titres increased only in participants who were colonised with N lactamica for 14 days.

INTERPRETATION

Natural immunity to N meningitidis after colonisation with N lactamica might be due to cross-reactive adaptive responses. Exploitation of this microbial mechanism with a genetically modified live vector could protect against N meningitidis colonisation and disease.

FUNDING

Wellcome Trust, Medical Research Council, and NIHR Southampton Biomedical Research Centre.

Efficacy, safety, and immunogenicity of a booster regimen of Ad26.COV2.S vaccine against COVID-19 (ENSEMBLE2): results of a randomised, double-blind, placebo-controlled, phase 3 trial

BACKGROUND

Despite the availability of effective vaccines against COVID-19, booster vaccinations are needed to maintain vaccine-induced protection against variant strains and breakthrough infections. This study aimed to investigate the efficacy, safety, and immunogenicity of the Ad26.COV2.S vaccine (Janssen) as primary vaccination plus a booster dose.

METHODS

ENSEMBLE2 is a randomised, double-blind, placebo-controlled, phase 3 trial including crossover vaccination after emergency authorisation of COVID-19 vaccines. Adults aged at least 18 years without previous COVID-19 vaccination at public and private medical practices and hospitals in Belgium, Brazil, Colombia, France, Germany, the Philippines, South Africa, Spain, the UK, and the USA were randomly assigned 1:1 via a computer algorithm to receive intramuscularly administered Ad26.COV2.S as a primary dose plus a booster dose at 2 months or two placebo injections 2 months apart. The primary endpoint was vaccine efficacy against the first occurrence of molecularly confirmed moderate to severe-critical COVID-19 with onset at least 14 days after booster vaccination, which was assessed in participants who received two doses of vaccine or placebo, were negative for SARS-CoV-2 by PCR at baseline and on serology at baseline and day 71, had no major protocol deviations, and were at risk of COVID-19 (ie, had no PCR-positive result or discontinued the study before day 71). Safety was assessed in all participants; reactogenicity, in terms of solicited local and systemic adverse events, was assessed as a secondary endpoint in a safety subset (approximately 6000 randomly selected participants). The trial is registered with ClinicalTrials.gov, NCT04614948, and is ongoing.

FINDINGS

Enrolment began on Nov 16, 2020, and the primary analysis data cutoff was June 25, 2021. From 34 571 participants screened, the double-blind phase enrolled 31 300 participants, 14 492 of whom received two doses (7484 in the Ad26.COV2.S group and 7008 in the placebo group) and 11 639 of whom were eligible for inclusion in the assessment of the primary endpoint (6024 in the Ad26.COV2.S group and 5615 in the placebo group). The median (IQR) follow-up post-booster vaccination was 36·0 (15·0-62·0) days. Vaccine efficacy was 75·2% (adjusted 95% CI 54·6-87·3) against moderate to severe-critical COVID-19 (14 cases in the Ad26.COV2.S group and 52 cases in the placebo group). Most cases were due to the variants alpha (B.1.1.7) and mu (B.1.621); endpoints for the primary analysis accrued from Nov 16, 2020, to June 25, 2021, before the global dominance of delta (B.1.617.2) or omicron (B.1.1.529). The booster vaccine exhibited an acceptable safety profile. The overall frequencies of solicited local and systemic adverse events (evaluated in the safety subset, n=6067) were higher among vaccine recipients than placebo recipients after the primary and booster doses. The frequency of solicited adverse events in the Ad26.COV2.S group were similar following the primary and booster vaccinations (local adverse events, 1676 [55·6%] of 3015 vs 896 [57·5%] of 1559, respectively; systemic adverse events, 1764 [58·5%] of 3015 vs 821 [52·7%] of 1559, respectively). Solicited adverse events were transient and mostly grade 1-2 in severity.

INTERPRETATION

A homologous Ad26.COV2.S booster administered 2 months after primary single-dose vaccination in adults had an acceptable safety profile and was efficacious against moderate to severe-critical COVID-19. Studies assessing efficacy against newer variants and with longer follow-up are needed.

FUNDING

Janssen Research & Development.

Parental concern for clinically vulnerable child during first 18 months of the COVID pandemic

BACKGROUND

The uncertainties surrounding the COVID-19 pandemic have been associated with increased parental concern. The aim of this study is to explore if this increased level of concern is associated with certain individual/household characteristics or if parents adapted to the ever-changing realities of the COVID-19 pandemic over time.

METHODS

This prospective study explored COVID-19 concern trajectories and associated family characteristics of 765 UK parents caring for an immunosuppressed child during the first 18 months of the pandemic using growth mixture modelling. Qualitative analysis was performed to examine in more detail the source of concern.

RESULTS

Four different trajectories of parental COVID-19 concern were identified. Ongoing very high concern was associated with caring for children with nephrotic or respiratory disease; having a child on an organ transplant waiting list; residency in the North of England; or parental vocational inactivity. Explicit concerns voiced by the parents generally followed national trends, but vulnerable status specific concerns were also reported.

CONCLUSION

Diagnosis and prescribed medication of the immunosuppressed child, geographical location, household composition, and employment status of parent were associated with the different concern trajectories. This information can be helpful in targeting psychological family care where it is most needed.

IMPACT

Many British parents caring for a clinically vulnerable child during the first 18 months of the COVID-19 pandemic showed high levels of concern with little sign of psychological adaptation. Consistent with findings from non-vulnerable populations, parents mentioned the impact of shielding and repeated isolation on their child's education, social life, and mental health. Unique to the clinically vulnerable population, parents were worried about child's health status, impact of delayed healthcare, and were confused by the contradictory information received from government, doctors, and media. Psychological family care can be targeted to those parents at greater risk for high levels of concern.

Phase 1/2a Safety and Immunogenicity of an Adenovirus 26 Vector Respiratory Syncytial Virus (RSV) Vaccine Encoding Prefusion F in Adults 18-50 Years and RSV-Seropositive Children 12-24 Months

BACKGROUND

Respiratory syncytial virus (RSV) remains a leading cause of pediatric morbidity, with no approved vaccine. We assessed the safety and immunogenicity of the Ad26.RSV.preF vaccine candidate in adults and children.

METHODS

In this randomized, double-blind, phase 1/2a, placebo-controlled study, 12 adults (18-50 years) and 36 RSV-seropositive children (12-24 months) were randomized 2:1 to Ad26.RSV.preF (1 × 1011 viral particles [vp] for adults, 5 × 1010 vp for children) or placebo, at day 1 and 29, with 6-month immunogenicity and 1-year safety follow-up. Respiratory syncytial virus infection was an exploratory outcome in children.

RESULTS

In adults, solicited adverse events (AEs) were generally mild to moderate, with no serious AEs. In children, no vaccination-related serious AEs were reported; fever was reported in 14 (58.3%) Ad26.RSV.preF recipients. Baseline pediatric geometric mean titers for RSV A2 neutralization increased from 121 (95% confidence interval [CI], 76-191) to 1608 (95% CI, 730-3544) at day 29, and 2235 (95% CI, 1586-3150) at day 57, remaining elevated over 7 months. Respiratory syncytial virus infection was confirmed in fewer children receiving Ad26.RSV.preF (1, 4.2%) than placebo (5, 41.7%).

CONCLUSIONS

Ad26.RSV.preF demonstrated immunogenicity in healthy adults and toddlers, with no safety concerns raised. Evaluations in RSV-seronegative children are underway.

Safety and immunogenicity of the inactivated whole-virus adjuvanted COVID-19 vaccine VLA2001: A randomized, dose escalation, double-blind phase 1/2 clinical trial in healthy adults

OBJECTIVES

We aimed to evaluate the safety and optimal dose of a novel inactivated whole-virus adjuvanted vaccine against SARS-CoV-2: VLA2001.

METHODS

We conducted an open-label, dose-escalation study followed by a double-blind randomized trial using low, medium and high doses of VLA2001 (1:1:1). The primary safety outcome was the frequency and severity of solicited local and systemic reactions within 7 days after vaccination. The primary immunogenicity outcome was the geometric mean titre (GMT) of neutralizing antibodies against SARS-CoV-2 two weeks after the second vaccination. The study is registered as NCT04671017.

RESULTS

Between December 16, 2020, and June 3, 2021, 153 healthy adults aged 18-55 years were recruited in the UK. Overall, 81.7% of the participants reported a solicited AE, with injection site tenderness (58.2%) and headache (46.4%) being the most frequent. Only 2 participants reported a severe solicited event. Up to day 106, 131 (85.6%) participants had reported any AE. All observed incidents were transient and non-life threatening in nature. Immunogenicity measured at 2 weeks after completion of the two-dose priming schedule, showed significantly higher GMTs of SARS-CoV-2 neutralizing antibody titres in the highest dose group (GMT 545.6; 95% CI: 428.1, 695.4) which were similar to a panel of convalescent sera (GMT 526.9; 95% CI: 336.5, 825.1). Seroconversion rates of neutralizing antibodies were also significantly higher in the high-dose group (>90%) compared to the other dose groups. In the high dose group, antigen-specific IFN-γ expressing T-cells reactive against the S, M and N proteins were observed in 76, 36 and 49%, respectively.

CONCLUSIONS

VLA2001 was well tolerated in all tested dose groups, and no safety signal of concern was identified. The highest dose group showed statistically significantly stronger immunogenicity with similar tolerability and safety, and was selected for phase 3 clinical development.

Safety, immunogenicity, and reactogenicity of BNT162b2 and mRNA-1273 COVID-19 vaccines given as fourth-dose boosters following two doses of ChAdOx1 nCoV-19 or BNT162b2 and a third dose of BNT162b2 (COV-BOOST): a multicentre, blinded, phase 2, randomised trial

BACKGROUND

Some high-income countries have deployed fourth doses of COVID-19 vaccines, but the clinical need, effectiveness, timing, and dose of a fourth dose remain uncertain. We aimed to investigate the safety, reactogenicity, and immunogenicity of fourth-dose boosters against COVID-19.

METHODS

The COV-BOOST trial is a multicentre, blinded, phase 2, randomised controlled trial of seven COVID-19 vaccines given as third-dose boosters at 18 sites in the UK. This sub-study enrolled participants who had received BNT162b2 (Pfizer-BioNTech) as their third dose in COV-BOOST and randomly assigned them (1:1) to receive a fourth dose of either BNT162b2 (30 μg in 0·30 mL; full dose) or mRNA-1273 (Moderna; 50 μg in 0·25 mL; half dose) via intramuscular injection into the upper arm. The computer-generated randomisation list was created by the study statisticians with random block sizes of two or four. Participants and all study staff not delivering the vaccines were masked to treatment allocation. The coprimary outcomes were safety and reactogenicity, and immunogenicity (anti-spike protein IgG titres by ELISA and cellular immune response by ELISpot). We compared immunogenicity at 28 days after the third dose versus 14 days after the fourth dose and at day 0 versus day 14 relative to the fourth dose. Safety and reactogenicity were assessed in the per-protocol population, which comprised all participants who received a fourth-dose booster regardless of their SARS-CoV-2 serostatus. Immunogenicity was primarily analysed in a modified intention-to-treat population comprising seronegative participants who had received a fourth-dose booster and had available endpoint data. This trial is registered with ISRCTN, 73765130, and is ongoing.

FINDINGS

Between Jan 11 and Jan 25, 2022, 166 participants were screened, randomly assigned, and received either full-dose BNT162b2 (n=83) or half-dose mRNA-1273 (n=83) as a fourth dose. The median age of these participants was 70·1 years (IQR 51·6-77·5) and 86 (52%) of 166 participants were female and 80 (48%) were male. The median interval between the third and fourth doses was 208·5 days (IQR 203·3-214·8). Pain was the most common local solicited adverse event and fatigue was the most common systemic solicited adverse event after BNT162b2 or mRNA-1273 booster doses. None of three serious adverse events reported after a fourth dose with BNT162b2 were related to the study vaccine. In the BNT162b2 group, geometric mean anti-spike protein IgG concentration at day 28 after the third dose was 23 325 ELISA laboratory units (ELU)/mL (95% CI 20 030-27 162), which increased to 37 460 ELU/mL (31 996-43 857) at day 14 after the fourth dose, representing a significant fold change (geometric mean 1·59, 95% CI 1·41-1·78). There was a significant increase in geometric mean anti-spike protein IgG concentration from 28 days after the third dose (25 317 ELU/mL, 95% CI 20 996-30 528) to 14 days after a fourth dose of mRNA-1273 (54 936 ELU/mL, 46 826-64 452), with a geometric mean fold change of 2·19 (1·90-2·52). The fold changes in anti-spike protein IgG titres from before (day 0) to after (day 14) the fourth dose were 12·19 (95% CI 10·37-14·32) and 15·90 (12·92-19·58) in the BNT162b2 and mRNA-1273 groups, respectively. T-cell responses were also boosted after the fourth dose (eg, the fold changes for the wild-type variant from before to after the fourth dose were 7·32 [95% CI 3·24-16·54] in the BNT162b2 group and 6·22 [3·90-9·92] in the mRNA-1273 group).

INTERPRETATION

Fourth-dose COVID-19 mRNA booster vaccines are well tolerated and boost cellular and humoral immunity. Peak responses after the fourth dose were similar to, and possibly better than, peak responses after the third dose.

FUNDING

UK Vaccine Task Force and National Institute for Health Research.

Community seroprevalence of SARS-CoV-2 in children and adolescents in England, 2019-2021

OBJECTIVE

To understand community seroprevalence of SARS-CoV-2 in children and adolescents. This is vital to understanding the susceptibility of this cohort to COVID-19 and to inform public health policy for disease control such as immunisation.

DESIGN

We conducted a community-based cross-sectional seroprevalence study in participants aged 0-18 years old recruiting from seven regions in England between October 2019 and June 2021 and collecting extensive demographic and symptom data. Serum samples were tested for antibodies against SARS-CoV-2 spike and nucleocapsid proteins using Roche assays processed at UK Health Security Agency laboratories. Prevalence estimates were calculated for six time periods and were standardised by age group, ethnicity and National Health Service region.

RESULTS

Post-first wave (June-August 2020), the (anti-spike IgG) adjusted seroprevalence was 5.2%, varying from 0.9% (participants 10-14 years old) to 9.5% (participants 5-9 years old). By April-June 2021, this had increased to 19.9%, varying from 13.9% (participants 0-4 years old) to 32.7% (participants 15-18 years old). Minority ethnic groups had higher risk of SARS-CoV-2 seropositivity than white participants (OR 1.4, 95% CI 1.0 to 2.0), after adjusting for sex, age, region, time period, deprivation and urban/rural geography. In children <10 years, there were no symptoms or symptom clusters that reliably predicted seropositivity. Overall, 48% of seropositive participants with complete questionnaire data recalled no symptoms between February 2020 and their study visit.

CONCLUSIONS

Approximately one-third of participants aged 15-18 years old had evidence of antibodies against SARS-CoV-2 prior to the introduction of widespread vaccination. These data demonstrate that ethnic background is independently associated with risk of SARS-CoV-2 infection in children.

TRIAL REGISTRATION NUMBER

NCT04061382.

Impact of meningococcal ACWY conjugate vaccines on pharyngeal carriage in adolescents: evidence for herd protection from the UK MenACWY programme

OBJECTIVES

Serogroup W and Y invasive meningococcal disease (IMD) increased globally from 2000 onwards. Responding to a rapid increase in serogroup W clonal complex 11 (W:cc11) IMD, the UK replaced an adolescent booster dose of meningococcal C conjugate vaccine with quadrivalent MenACWY conjugate vaccine in 2015. By 2018, vaccine coverage in the eligible school cohorts aged 14-19 years-old was 84%. We assessed the impact of the MenACWY vaccination programme on meningococcal carriage.

METHODS

An observational study of culture-defined oropharyngeal meningococcal carriage prevalence before and after the start of the MenACWY vaccination programme in UK school students, aged 15-19 years, using two cross-sectional studies: 2014-15 "UKMenCar4" and 2018 "Be on the TEAM" (ISRCTN75858406).

RESULTS

A total of 10625 participants pre-implementation and 13434 post-implementation were included. Carriage of genogroups C, W, and Y (combined) decreased from 2·03% to 0·71% (OR 0·34 [95% CI 0·27-0·44] p<0·001). Carriage of genogroup B meningococci did not change (1·26% vs 1·23% [95% CI 0.77-1.22] p=0·80) and genogroup C remained rare (n = 7/10625 vs 17/13488, p=0·135). The proportion of serogroup positive isolates, i.e., those expressing capsule, decreased for genogroup W by 53.8% (95% CI -5.0%-79.8%, p=0·016) and for genogroup Y by 30·1% (95% CI 8·9%-46·3%, p=0·0025).

CONCLUSIONS

The UK MenACWY vaccination programme reduced carriage acquisition of genogroup and serogroup Y and W meningococci and sustained low levels of genogroup C carriage. These data support the use of quadrivalent MenACWY conjugate vaccine for indirect (herd) protection.

Safety and immunogenicity of the ChAdOx1 nCoV-19 (AZD1222) vaccine in children aged 6-17 years: a preliminary report of COV006, a phase 2 single-blind, randomised, controlled trial

BACKGROUND

Vaccination of children and young people against SARS-CoV-2 is recommended in some countries. Scarce data have been published on immune responses induced by COVID-19 vaccines in people younger than 18 years compared with the same data that are available in adults.

METHODS

COV006 is a phase 2, single-blind, randomised, controlled trial of ChAdOx1 nCoV-19 (AZD1222) in children and adolescents at four trial sites in the UK. Healthy participants aged 6-17 years, who did not have a history of chronic respiratory conditions, laboratory-confirmed COVID-19, or previously received capsular group B meningococcal vaccine (the control), were randomly assigned to four groups (4:1:4:1) to receive two intramuscular doses of 5 × 10¹⁰ viral particles of ChAdOx1 nCoV-19 or control, 28 days or 84 days apart. Participants, clinical investigators, and the laboratory team were masked to treatment allocation. Study groups were stratified by age, and participants aged 12-17 years were enrolled before those aged 6-11 years. Due to the restrictions in the use of ChAdOx1 nCoV-19 in people younger than 30 years that were introduced during the study, only participants aged 12-17 years who were randomly assigned to the 28-day interval group had received their vaccinations at the intended interval (day 28). The remaining participants received their second dose at day 112. The primary outcome was assessment of safety and tolerability in the safety population, which included all participants who received at least one dose of the study drug. The secondary outcome was immunogenicity, which was assessed in participants who were seronegative to the nucleocapsid protein at baseline and received both prime and boost vaccine. This study is registered with ISRCTN (15638344).

FINDINGS

Between Feb 15 and April 2, 2021, 262 participants (150 [57%] participants aged 12-17 years and 112 [43%] aged 6-11 years; due to the change in the UK vaccination policy, the study terminated recruitment of the younger age group before the planned number of participants had been enrolled) were randomly assigned to receive vaccination with two doses of either ChAdOx1 nCoV-19 (n=211 [n=105 at day 28 and n=106 at day 84]) or control (n=51 [n=26 at day 28 and n=25 at day 84]). One participant in the ChAdOx1 nCoV-19 day 28 group in the younger age bracket withdrew their consent before receiving a first dose. Of the participants who received ChAdOx1 nCoV-19, 169 (80%) of 210 participants reported at least one solicited local or systemic adverse event up to 7 days following the first dose, and 146 (76%) of 193 participants following the second dose. No serious adverse events related to ChAdOx1 nCoV-19 administration were recorded by the data cutoff date on Oct 28, 2021. Of the participants who received at least one dose of ChAdOx1 nCoV-19, there were 128 unsolicited adverse events up to 28 days after vaccination reported by 83 (40%) of 210 participants. One participant aged 6-11 years receiving ChAdOx1 nCoV-19 reported a grade 4 fever of 40·2°C on day 1 following first vaccination, which resolved within 24 h. Pain and tenderness were the most common local solicited adverse events for all the ChAdOx1 nCoV-19 and capsular group B meningococcal groups following both doses. Of the 242 participants with available serostatus data, 14 (6%) were seropositive at baseline. Serostatus data were not available for 20 (8%) of 262 participants. Among seronegative participants who received ChAdOx1 nCoV-19, anti-SARS-CoV-2 IgG and pseudoneutralising antibody titres at day 28 after the second dose were higher in participants aged 12-17 years with a longer interval between doses (geometric means of 73 371 arbitrary units [AU]/mL [95% CI 58 685-91 733] and 299 half-maximal inhibitory concentration [IC₅₀; 95% CI 230-390]) compared with those aged 12-17 years who received their vaccines 28 days apart (43 280 AU/mL [95% CI 35 852-52 246] and 150 IC₅₀ [95% CI 116-194]). Humoral responses were higher in those aged 6-11 years than in those aged 12-17 years receiving their second dose at the same 112-day interval (geometric mean ratios 1·48 [95% CI 1·07-2·07] for anti-SARS-CoV-2 IgG and 2·96 [1·89-4·62] for pseudoneutralising antibody titres). Cellular responses peaked after a first dose of ChAdOx1 nCoV-19 across all age and interval groups and remained above baseline after a second vaccination.

INTERPRETATION

ChAdOx1 nCoV-19 is well tolerated and immunogenic in children aged 6-17 years, inducing concentrations of antibody that are similar to those associated with high efficacy in phase 3 studies in adults. No safety concerns were raised in this trial.

FUNDING

AstraZeneca and the UK Department of Health and Social Care through the UK National Institute for Health and Care Research.

Persistence of immunogenicity after seven COVID-19 vaccines given as third dose boosters following two doses of ChAdOx1 nCov-19 or BNT162b2 in the UK: Three month analyses of the COV-BOOST trial

OBJECTIVES

To evaluate the persistence of immunogenicity three months after third dose boosters.

METHODS

COV-BOOST is a multicentre, randomised, controlled, phase 2 trial of seven COVID-19 vaccines used as a third booster dose. The analysis was conducted using all randomised participants who were SARS-CoV-2 naïve during the study.

RESULTS

Amongst the 2883 participants randomised, there were 2422 SARS-CoV-2 naïve participants until D84 visit included in the analysis with median age of 70 (IQR: 30-94) years. In the participants who had two initial doses of ChAdOx1 nCov-19 (Oxford-AstraZeneca; hereafter referred to as ChAd), schedules using mRNA vaccines as third dose have the highest anti-spike IgG at D84 (e.g. geometric mean concentration of 8674 ELU/ml (95% CI: 7461-10,085) following ChAd/ChAd/BNT162b2 (Pfizer-BioNtech, hearafter referred to as BNT)). However, in people who had two initial doses of BNT there was no significant difference at D84 in people given ChAd versus BNT (geometric mean ratio (GMR) of 0.95 (95%CI: 0.78, 1.15). Also, people given Ad26.COV2.S (Janssen; hereafter referred to as Ad26) as a third dose had significantly higher anti-spike IgG at D84 than BNT (GMR of 1.20, 95%CI: 1.01,1.43). Responses at D84 between people who received BNT (15 μg) or BNT (30 μg) after ChAd/ChAd or BNT/BNT were similar, with anti-spike IgG GMRs of half-BNT (15 μg) versus BNT (30 μg) ranging between 0.74-0.86. The decay rate of cellular responses were similar between all the vaccine schedules and doses.

CONCLUSIONS

84 days after a third dose of COVID-19 vaccine the decay rates of humoral response were different between vaccines. Adenoviral vector vaccine anti-spike IgG concentrations at D84 following BNT/BNT initial doses were similar to or even higher than for a three dose (BNT/BNT/BNT) schedule. Half dose BNT immune responses were similar to full dose responses. While high antibody tires are desirable in situations of high transmission of new variants of concern, the maintenance of immune responses that confer long-lasting protection against severe disease or death is also of critical importance. Policymakers may also consider adenoviral vector, fractional dose of mRNA, or other non-mRNA vaccines as third doses.

Multicenter Randomized Trial of Methylprednisolone vs. Intravenous Immunoglobulins to Treat the Pediatric Inflammatory Multisystem Syndrome-Temporally Associated With SARS-CoV-2 (PIMS-TS): Protocol of the Swissped RECOVERY Trial

Introduction

In 2020, a new disease entitled Pediatric Inflammatory Multisystem Syndrome temporally associated with COVID-19 (PIMS-TS), or Multisystem Inflammatory Syndrome in Children (MIS-C), emerged, with thousands of children affected globally. There is no available evidence based on randomized controlled trials (RCT) to date on the two most commonly used immunomodulatory treatments, intravenous immunoglobulins (IVIG) and corticosteroids. Therefore, the Swissped RECOVERY trial was conducted to assess whether intravenous (IV) methylprednisolone shortens hospital length of stay compared with IVIG.

Methods and Analysis

Swissped RECOVERY is an ongoing investigator-initiated, open-label, multicenter two-arm RCT in children and adolescents <18 years hospitalized with a diagnosis of PIMS-TS. The trial is recruiting at 10 sites across Switzerland. Patients diagnosed with PIMS-TS are randomized 1:1 to methylprednisolone IV (10 mg/kg/day for 3 days) or IVIG (2 g/kg as a single dose). The primary outcome is hospital length of stay censored at day 28, death, or discharge (whichever is first). The target total sample size is ~80 patients 1:1 randomized to each study arm. Ancillary and exploratory studies on inflammation, vaccination acceptance and coverage, long-term outcomes, and healthcare costs are pre-planned.

Significance

Currently, robust trial evidence for the treatment of PIMS-TS is lacking, with a controversy surrounding the use of corticosteroids vs. IVIG. This trial will provide evidence for the effectiveness and safety of these two treatments.

Ethics and Dissemination

The study protocol, which was designed based on the U.K. RECOVERY trial, the patient information and consent forms, and other study-specific study documents were approved by the local ethics committees (Project ID: 2021-00362).

Registration Details

The study is registered on the Swiss National Clinical Trials Portal (SNCTP000004720) and Clinicaltrials.gov (NCT04826588).

Immune responses against SARS-CoV-2 variants after two and three doses of vaccine in B-cell malignancies: UK PROSECO study

Patients with hematological malignancies are at increased risk of severe COVID-19 outcomes due to compromised immune responses, but the insights of these studies have been compromised due to intrinsic limitations in study design. Here we present the PROSECO prospective observational study ( NCT04858568 ) on 457 patients with lymphoma that received two or three COVID-19 vaccine doses. We show undetectable humoral responses following two vaccine doses in 52% of patients undergoing active anticancer treatment. Moreover, 60% of patients on anti-CD20 therapy had undetectable antibodies following full vaccination within 12 months of receiving their anticancer therapy. However, 70% of individuals with indolent B-cell lymphoma displayed improved antibody responses following booster vaccination. Notably, 63% of all patients displayed antigen-specific T-cell responses, which increased after a third dose irrespective of their cancer treatment status. Our results emphasize the urgency of careful monitoring of COVID-19-specific immune responses to guide vaccination schemes in these vulnerable populations.

Incidental findings in UK healthy volunteers screened for a COVID-19 vaccine trial

The safety of novel therapeutics and vaccines are typically assessed in early phase clinical trials involving "healthy volunteers." Abnormalities in such individuals can be difficult to interpret and may indicate previously unrecognized medical conditions. The frequency of incidental findings (IFs) in healthy volunteers who attend for clinical trial screening is unclear. To assess this, we retrospectively analyzed data for 1838 "healthy volunteers" screened for enrolment in a UK multicenter, phase I/II severe acute respiratory syndrome-coronavirus 2 (SARS-COV-2) vaccine trial. Participants were predominantly White (89.7%, 1640/1828) with a median age of 34 years (interquartile range [IQR] = 27-44). There were 27.7% of participants (510/1838) who had at least one IF detected. The likelihood of identifying evidence of a potential, new blood-borne virus infection was low (1 in 238 participants) compared with identification of an elevated alanine transaminase (ALT; 1 in 17 participants). A large proportion of participants described social habits that could impact negatively on their health; 21% consumed alcohol in excess, 10% were current smokers, 11% described recreational drug use, and only 48% had body weight in the ideal range. Our data demonstrate that screening prior to enrollment in early phase clinical trials identifies a range of IFs, which should inform discussion during the consent process. Greater clarity is needed to ensure an appropriate balance is struck between early identification of medical problems and avoidance of exclusion of volunteers due to spurious or physiological abnormalities. Debate should inform the role of the trial physician in highlighting and advising about unhealthy social habits.

Safety and immunogenicity of a self-amplifying RNA vaccine against COVID-19: COVAC1, a phase I, dose-ranging trial

BACKGROUND

Lipid nanoparticle (LNP) encapsulated self-amplifying RNA (saRNA) is a novel technology formulated as a low dose vaccine against COVID-19.

METHODS

A phase I first-in-human dose-ranging trial of a saRNA COVID-19 vaccine candidate LNP-nCoVsaRNA, was conducted at Imperial Clinical Research Facility, and participating centres in London, UK, between 19^th June to 28^th October 2020. Participants received two intramuscular (IM) injections of LNP-nCoVsaRNA at six different dose levels, 0.1-10.0μg, given four weeks apart. An open-label dose escalation was followed by a dose evaluation. Solicited adverse events (AEs) were collected for one week from enrolment, with follow-up at regular intervals (1-8 weeks). The binding and neutralisation capacity of anti-SARS-CoV-2 antibody raised in participant sera was measured by means of an anti-Spike (S) IgG ELISA, immunoblot, SARS-CoV-2 pseudoneutralisation and wild type neutralisation assays. (The trial is registered: ISRCTN17072692, EudraCT 2020-001646-20).

FINDINGS

192 healthy individuals with no history or serological evidence of COVID-19, aged 18-45 years were enrolled. The vaccine was well tolerated with no serious adverse events related to vaccination. Seroconversion at week six whether measured by ELISA or immunoblot was related to dose (both p<0.001), ranging from 8% (3/39; 0.1μg) to 61% (14/23; 10.0μg) in ELISA and 46% (18/39; 0.3μg) to 87% (20/23; 5.0μg and 10.0μg) in a post-hoc immunoblot assay. Geometric mean (GM) anti-S IgG concentrations ranged from 74 (95% CI, 45-119) at 0.1μg to 1023 (468-2236) ng/mL at 5.0μg (p<0.001) and was not higher at 10.0μg. Neutralisation of SARS-CoV-2 by participant sera was measurable in 15% (6/39; 0.1μg) to 48% (11/23; 5.0μg) depending on dose level received.

INTERPRETATION

Encapsulated saRNA is safe for clinical development, is immunogenic at low dose levels but failed to induce 100% seroconversion. Modifications to optimise humoral responses are required to realise its potential as an effective vaccine against SARS-CoV-2.

FUNDING

This study was co-funded by grants and gifts from the Medical Research Council UKRI (MC_PC_19076), and the National Institute Health Research/Vaccine Task Force, Partners of Citadel and Citadel Securities, Sir Joseph Hotung Charitable Settlement, Jon Moulton Charity Trust, Pierre Andurand, Restore the Earth.

Biomarker-guided duration of Antibiotic Treatment in Children Hospitalised with confirmed or suspected bacterial infection (BATCH): protocol for a randomised controlled trial

INTRODUCTION

Procalcitonin (PCT) is a biomarker more specific for bacterial infection and responds quicker than other commonly used biomarkers such as C reactive protein, but is not routinely used in the National Health Service (NHS). Studies mainly in adults show that using PCT to guide clinicians may reduce antibiotic use, reduce hospital stay, with no associated adverse effects such as increased rates of hospital re-admission, incomplete treatment of infections, relapse or death. A review conducted for National Institute for Health and Care Excellence recommends further research on PCT testing to guide antibiotic use in children.

METHODS AND ANALYSIS

Biomarker-guided duration of Antibiotic Treatment in Children Hospitalised with confirmed or suspected bacterial infection is a multi-centre, prospective, two-arm, individually Randomised Controlled Trial (RCT) with a 28-day follow-up and internal pilot. The intervention is a PCT-guided algorithm used in conjunction with best practice. The control arm is best practice alone. We plan to recruit 1942 children, aged between 72 hours and up to 18 years old, who are admitted to the hospital and being treated with intravenous antibiotics for suspected or confirmed bacterial infection. Coprimary outcomes are duration of antibiotic use and a composite safety measure. Secondary outcomes include time to switch from broad to narrow spectrum antibiotics, time to discharge, adverse drug reactions, health utility and cost-effectiveness. We will also perform a qualitative process evaluation. Recruitment commenced in June 2018 and paused briefly between March and May 2020 due to the COVID-19 pandemic.

ETHICS AND DISSEMINATION

The trial protocol was approved by the HRA and NHS REC (North West Liverpool East REC reference 18/NW/0100). We will publish the results in international peer-reviewed journals and present at scientific meetings.

TRIAL REGISTRATION NUMBER

ISRCTN11369832.

Immunogenicity, safety, and reactogenicity of heterologous COVID-19 primary vaccination incorporating mRNA, viral-vector, and protein-adjuvant vaccines in the UK (Com-COV2): a single-blind, randomised, phase 2, non-inferiority trial

BACKGROUND

Given the importance of flexible use of different COVID-19 vaccines within the same schedule to facilitate rapid deployment, we studied mixed priming schedules incorporating an adenoviral-vectored vaccine (ChAdOx1 nCoV-19 [ChAd], AstraZeneca), two mRNA vaccines (BNT162b2 [BNT], Pfizer-BioNTech, and mRNA-1273 [m1273], Moderna) and a nanoparticle vaccine containing SARS-CoV-2 spike glycoprotein and Matrix-M adjuvant (NVX-CoV2373 [NVX], Novavax).

METHODS

Com-COV2 is a single-blind, randomised, non-inferiority trial in which adults aged 50 years and older, previously immunised with a single dose of ChAd or BNT in the community, were randomly assigned (in random blocks of three and six) within these cohorts in a 1:1:1 ratio to receive a second dose intramuscularly (8-12 weeks after the first dose) with the homologous vaccine, m1273, or NVX. The primary endpoint was the geometric mean ratio (GMR) of serum SARS-CoV-2 anti-spike IgG concentrations measured by ELISA in heterologous versus homologous schedules at 28 days after the second dose, with a non-inferiority criterion of the GMR above 0·63 for the one-sided 98·75% CI. The primary analysis was on the per-protocol population, who were seronegative at baseline. Safety analyses were done for all participants who received a dose of study vaccine. The trial is registered with ISRCTN, number 27841311.

FINDINGS

Between April 19 and May 14, 2021, 1072 participants were enrolled at a median of 9·4 weeks after receipt of a single dose of ChAd (n=540, 47% female) or BNT (n=532, 40% female). In ChAd-primed participants, geometric mean concentration (GMC) 28 days after a boost of SARS-CoV-2 anti-spike IgG in recipients of ChAd/m1273 (20 114 ELISA laboratory units [ELU]/mL [95% CI 18 160 to 22 279]) and ChAd/NVX (5597 ELU/mL [4756 to 6586]) was non-inferior to that of ChAd/ChAd recipients (1971 ELU/mL [1718 to 2262]) with a GMR of 10·2 (one-sided 98·75% CI 8·4 to ∞) for ChAd/m1273 and 2·8 (2·2 to ∞) for ChAd/NVX, compared with ChAd/ChAd. In BNT-primed participants, non-inferiority was shown for BNT/m1273 (GMC 22 978 ELU/mL [95% CI 20 597 to 25 636]) but not for BNT/NVX (8874 ELU/mL [7391 to 10 654]), compared with BNT/BNT (16 929 ELU/mL [15 025 to 19 075]) with a GMR of 1·3 (one-sided 98·75% CI 1·1 to ∞) for BNT/m1273 and 0·5 (0·4 to ∞) for BNT/NVX, compared with BNT/BNT; however, NVX still induced an 18-fold rise in GMC 28 days after vaccination. There were 15 serious adverse events, none considered related to immunisation.

INTERPRETATION

Heterologous second dosing with m1273, but not NVX, increased transient systemic reactogenicity compared with homologous schedules. Multiple vaccines are appropriate to complete primary immunisation following priming with BNT or ChAd, facilitating rapid vaccine deployment globally and supporting recognition of such schedules for vaccine certification.

FUNDING

UK Vaccine Task Force, Coalition for Epidemic Preparedness Innovations (CEPI), and National Institute for Health Research. NVX vaccine was supplied for use in the trial by Novavax.

Immunocompromised children and young people are at no increased risk of severe COVID-19

OBJECTIVES

We aimed to prospectively describe the incidence and clinical spectrum of SARS-CoV-2 infection in immunocompromised paediatric patients in the UK.

METHODS

From March 2020 to 2021 weekly questionnaires were sent to immunocompromised paediatric patients or their parents. Information, including symptom presentation and SARS-CoV-2 PCR test results, was collected from 1527 participants from 46 hospitals. Cross-sectional serology was investigated in February and March 2021.

RESULTS

Until the end of September 2020, no cases were reported. From September 28th 2020 to March 2021 a total of 38 PCR-detected SARS-CoV-2 infections were reported. Of these, four children were admitted to hospital but none had acute severe COVID-19. Increasing age in association with immunodeficiency increased reporting of SARS-CoV-2 infection. Worsening of fever, cough, and sore throat were associated with participants reporting SARS-CoV-2 infection. Serology data included 452 unvaccinated participants. In those reporting prior positive SARS-CoV-2 PCR, there were detectable antibodies in 9 of 18 (50%). In those with no prior report of infection, antibodies were detected in 32 of 434 (7•4%).

CONCLUSIONS

This study shows SARS-CoV-2 infections have occurred in immunocompromised children and young people with no increased risk of severe disease. No children died.

Safety and immunogenicity of ChAdOx1 nCoV-19 vaccine administered in a prime-boost regimen in young and old adults (COV002): a single-blind, randomised, controlled, phase 2/3 trial

BACKGROUND

Older adults (aged ≥70 years) are at increased risk of severe disease and death if they develop COVID-19 and are therefore a priority for immunisation should an efficacious vaccine be developed. Immunogenicity of vaccines is often worse in older adults as a result of immunosenescence. We have reported the immunogenicity of a novel chimpanzee adenovirus-vectored vaccine, ChAdOx1 nCoV-19 (AZD1222), in young adults, and now describe the safety and immunogenicity of this vaccine in a wider range of participants, including adults aged 70 years and older.

METHODS

In this report of the phase 2 component of a single-blind, randomised, controlled, phase 2/3 trial (COV002), healthy adults aged 18 years and older were enrolled at two UK clinical research facilities, in an age-escalation manner, into 18-55 years, 56-69 years, and 70 years and older immunogenicity subgroups. Participants were eligible if they did not have severe or uncontrolled medical comorbidities or a high frailty score (if aged ≥65 years). First, participants were recruited to a low-dose cohort, and within each age group, participants were randomly assigned to receive either intramuscular ChAdOx1 nCoV-19 (2·2 × 1010 virus particles) or a control vaccine, MenACWY, using block randomisation and stratified by age and dose group and study site, using the following ratios: in the 18-55 years group, 1:1 to either two doses of ChAdOx1 nCoV-19 or two doses of MenACWY; in the 56-69 years group, 3:1:3:1 to one dose of ChAdOx1 nCoV-19, one dose of MenACWY, two doses of ChAdOx1 nCoV-19, or two doses of MenACWY; and in the 70 years and older, 5:1:5:1 to one dose of ChAdOx1 nCoV-19, one dose of MenACWY, two doses of ChAdOx1 nCoV-19, or two doses of MenACWY. Prime-booster regimens were given 28 days apart. Participants were then recruited to the standard-dose cohort (3·5-6·5 × 1010 virus particles of ChAdOx1 nCoV-19) and the same randomisation procedures were followed, except the 18-55 years group was assigned in a 5:1 ratio to two doses of ChAdOx1 nCoV-19 or two doses of MenACWY. Participants and investigators, but not staff administering the vaccine, were masked to vaccine allocation. The specific objectives of this report were to assess the safety and humoral and cellular immunogenicity of a single-dose and two-dose schedule in adults older than 55 years. Humoral responses at baseline and after each vaccination until 1 year after the booster were assessed using an in-house standardised ELISA, a multiplex immunoassay, and a live severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) microneutralisation assay (MNA80). Cellular responses were assessed using an ex-vivo IFN-γ enzyme-linked immunospot assay. The coprimary outcomes of the trial were efficacy, as measured by the number of cases of symptomatic, virologically confirmed COVID-19, and safety, as measured by the occurrence of serious adverse events. Analyses were by group allocation in participants who received the vaccine. Here, we report the preliminary findings on safety, reactogenicity, and cellular and humoral immune responses. This study is ongoing and is registered with ClinicalTrials.gov, NCT04400838, and ISRCTN, 15281137.

FINDINGS

Between May 30 and Aug 8, 2020, 560 participants were enrolled: 160 aged 18-55 years (100 assigned to ChAdOx1 nCoV-19, 60 assigned to MenACWY), 160 aged 56-69 years (120 assigned to ChAdOx1 nCoV-19: 40 assigned to MenACWY), and 240 aged 70 years and older (200 assigned to ChAdOx1 nCoV-19: 40 assigned to MenACWY). Seven participants did not receive the boost dose of their assigned two-dose regimen, one participant received the incorrect vaccine, and three were excluded from immunogenicity analyses due to incorrectly labelled samples. 280 (50%) of 552 analysable participants were female. Local and systemic reactions were more common in participants given ChAdOx1 nCoV-19 than in those given the control vaccine, and similar in nature to those previously reported (injection-site pain, feeling feverish, muscle ache, headache), but were less common in older adults (aged ≥56 years) than younger adults. In those receiving two standard doses of ChAdOx1 nCoV-19, after the prime vaccination local reactions were reported in 43 (88%) of 49 participants in the 18-55 years group, 22 (73%) of 30 in the 56-69 years group, and 30 (61%) of 49 in the 70 years and older group, and systemic reactions in 42 (86%) participants in the 18-55 years group, 23 (77%) in the 56-69 years group, and 32 (65%) in the 70 years and older group. As of Oct 26, 2020, 13 serious adverse events occurred during the study period, none of which were considered to be related to either study vaccine. In participants who received two doses of vaccine, median anti-spike SARS-CoV-2 IgG responses 28 days after the boost dose were similar across the three age cohorts (standard-dose groups: 18-55 years, 20 713 arbitrary units [AU]/mL [IQR 13 898-33 550], n=39; 56-69 years, 16 170 AU/mL [10 233-40 353], n=26; and ≥70 years 17 561 AU/mL [9705-37 796], n=47; p=0·68). Neutralising antibody titres after a boost dose were similar across all age groups (median MNA80 at day 42 in the standard-dose groups: 18-55 years, 193 [IQR 113-238], n=39; 56-69 years, 144 [119-347], n=20; and ≥70 years, 161 [73-323], n=47; p=0·40). By 14 days after the boost dose, 208 (>99%) of 209 boosted participants had neutralising antibody responses. T-cell responses peaked at day 14 after a single standard dose of ChAdOx1 nCoV-19 (18-55 years: median 1187 spot-forming cells [SFCs] per million peripheral blood mononuclear cells [IQR 841-2428], n=24; 56-69 years: 797 SFCs [383-1817], n=29; and ≥70 years: 977 SFCs [458-1914], n=48).

INTERPRETATION

ChAdOx1 nCoV-19 appears to be better tolerated in older adults than in younger adults and has similar immunogenicity across all age groups after a boost dose. Further assessment of the efficacy of this vaccine is warranted in all age groups and individuals with comorbidities.

FUNDING

UK Research and Innovation, National Institutes for Health Research (NIHR), Coalition for Epidemic Preparedness Innovations, NIHR Oxford Biomedical Research Centre, Thames Valley and South Midlands NIHR Clinical Research Network, and AstraZeneca.

Safety and immunogenicity of seven COVID-19 vaccines as a third dose (booster) following two doses of ChAdOx1 nCov-19 or BNT162b2 in the UK (COV-BOOST): a blinded, multicentre, randomised, controlled, phase 2 trial

BACKGROUND

Few data exist on the comparative safety and immunogenicity of different COVID-19 vaccines given as a third (booster) dose. To generate data to optimise selection of booster vaccines, we investigated the reactogenicity and immunogenicity of seven different COVID-19 vaccines as a third dose after two doses of ChAdOx1 nCov-19 (Oxford-AstraZeneca; hereafter referred to as ChAd) or BNT162b2 (Pfizer-BioNtech, hearafter referred to as BNT).

METHODS

COV-BOOST is a multicentre, randomised, controlled, phase 2 trial of third dose booster vaccination against COVID-19. Participants were aged older than 30 years, and were at least 70 days post two doses of ChAd or at least 84 days post two doses of BNT primary COVID-19 immunisation course, with no history of laboratory-confirmed SARS-CoV-2 infection. 18 sites were split into three groups (A, B, and C). Within each site group (A, B, or C), participants were randomly assigned to an experimental vaccine or control. Group A received NVX-CoV2373 (Novavax; hereafter referred to as NVX), a half dose of NVX, ChAd, or quadrivalent meningococcal conjugate vaccine (MenACWY)control (1:1:1:1). Group B received BNT, VLA2001 (Valneva; hereafter referred to as VLA), a half dose of VLA, Ad26.COV2.S (Janssen; hereafter referred to as Ad26) or MenACWY (1:1:1:1:1). Group C received mRNA1273 (Moderna; hereafter referred to as m1273), CVnCov (CureVac; hereafter referred to as CVn), a half dose of BNT, or MenACWY (1:1:1:1). Participants and all investigatory staff were blinded to treatment allocation. Coprimary outcomes were safety and reactogenicity and immunogenicity of anti-spike IgG measured by ELISA. The primary analysis for immunogenicity was on a modified intention-to-treat basis; safety and reactogenicity were assessed in the intention-to-treat population. Secondary outcomes included assessment of viral neutralisation and cellular responses. This trial is registered with ISRCTN, number 73765130.

FINDINGS

Between June 1 and June 30, 2021, 3498 people were screened. 2878 participants met eligibility criteria and received COVID-19 vaccine or control. The median ages of ChAd/ChAd-primed participants were 53 years (IQR 44-61) in the younger age group and 76 years (73-78) in the older age group. In the BNT/BNT-primed participants, the median ages were 51 years (41-59) in the younger age group and 78 years (75-82) in the older age group. In the ChAd/ChAD-primed group, 676 (46·7%) participants were female and 1380 (95·4%) were White, and in the BNT/BNT-primed group 770 (53·6%) participants were female and 1321 (91·9%) were White. Three vaccines showed overall increased reactogenicity: m1273 after ChAd/ChAd or BNT/BNT; and ChAd and Ad26 after BNT/BNT. For ChAd/ChAd-primed individuals, spike IgG geometric mean ratios (GMRs) between study vaccines and controls ranged from 1·8 (99% CI 1·5-2·3) in the half VLA group to 32·3 (24·8-42·0) in the m1273 group. GMRs for wild-type cellular responses compared with controls ranged from 1·1 (95% CI 0·7-1·6) for ChAd to 3·6 (2·4-5·5) for m1273. For BNT/BNT-primed individuals, spike IgG GMRs ranged from 1·3 (99% CI 1·0-1·5) in the half VLA group to 11·5 (9·4-14·1) in the m1273 group. GMRs for wild-type cellular responses compared with controls ranged from 1·0 (95% CI 0·7-1·6) for half VLA to 4·7 (3·1-7·1) for m1273. The results were similar between those aged 30-69 years and those aged 70 years and older. Fatigue and pain were the most common solicited local and systemic adverse events, experienced more in people aged 30-69 years than those aged 70 years or older. Serious adverse events were uncommon, similar in active vaccine and control groups. In total, there were 24 serious adverse events: five in the control group (two in control group A, three in control group B, and zero in control group C), two in Ad26, five in VLA, one in VLA-half, one in BNT, two in BNT-half, two in ChAd, one in CVn, two in NVX, two in NVX-half, and one in m1273.

INTERPRETATION

All study vaccines boosted antibody and neutralising responses after ChAd/ChAd initial course and all except one after BNT/BNT, with no safety concerns. Substantial differences in humoral and cellular responses, and vaccine availability will influence policy choices for booster vaccination.

FUNDING

UK Vaccine Taskforce and National Institute for Health Research.

AZD1222/ChAdOx1 nCoV-19 vaccination induces a polyfunctional spike protein-specific TH1 response with a diverse TCR repertoire

AZD1222 (ChAdOx1 nCoV-19), a replication-deficient simian adenovirus–vectored vaccine, has demonstrated safety, efficacy, and immunogenicity against coronavirus disease 2019 in clinical trials and real-world studies. We characterized CD4+ and CD8+ T cell responses induced by AZD1222 vaccination in peripheral blood mononuclear cells from 296 unique vaccine recipients aged 18 to 85 years who enrolled in the phase 2/3 COV002 trial. Total spike protein–specific CD4+ T cell helper type 1 (TH1) and CD8+ T cell responses were increased in AZD1222-vaccinated adults of all ages after two doses of AZD1222. CD4+ TH2 responses after AZD1222 vaccination were not detected. Furthermore, AZD1222-specific TH1 and CD8+ T cells both displayed a high degree of polyfunctionality in all adult age groups. T cell receptor β (TCRβ) sequences from vaccinated participants mapped against TCR sequences known to react to SARS-CoV-2 revealed substantial breadth and depth across the SARS-CoV-2 spike protein for both AZD1222-induced CD4+ and CD8+ T cell responses. Overall, AZD1222 vaccination induced a polyfunctional TH1-dominated T cell response, with broad CD4+ and CD8+ T cell coverage across the SARS-CoV-2 spike protein.

Amoxicillin duration and dose for community-acquired pneumonia in children: the CAP-IT factorial non-inferiority RCT

BACKGROUND

Data are limited regarding the optimal dose and duration of amoxicillin treatment for community-acquired pneumonia in children.

OBJECTIVES

To determine the efficacy, safety and impact on antimicrobial resistance of shorter (3-day) and longer (7-day) treatment with amoxicillin at both a lower and a higher dose at hospital discharge in children with uncomplicated community-acquired pneumonia.

DESIGN

A multicentre randomised double-blind 2 × 2 factorial non-inferiority trial in secondary care in the UK and Ireland.

SETTING

Paediatric emergency departments, paediatric assessment/observation units and inpatient wards.

PARTICIPANTS

Children aged > 6 months, weighing 6-24 kg, with a clinical diagnosis of community-acquired pneumonia, in whom treatment with amoxicillin as the sole antibiotic was planned on discharge.

INTERVENTIONS

Oral amoxicillin syrup at a dose of 35-50 mg/kg/day compared with a dose of 70-90 mg/kg/day, and 3 compared with 7 days' duration. Children were randomised simultaneously to each of the two factorial arms in a 1 : 1 ratio.

MAIN OUTCOME MEASURES

The primary outcome was clinically indicated systemic antibacterial treatment prescribed for respiratory tract infection (including community-acquired pneumonia), other than trial medication, up to 28 days after randomisation. Secondary outcomes included severity and duration of parent/guardian-reported community-acquired pneumonia symptoms, drug-related adverse events (including thrush, skin rashes and diarrhoea), antimicrobial resistance and adherence to trial medication.

RESULTS

A total of 824 children were recruited from 29 hospitals. Ten participants received no trial medication and were excluded. Participants [median age 2.5 (interquartile range 1.6-2.7) years; 52% male] were randomised to either 3 (n = 413) or 7 days (n = 401) of trial medication at either lower (n = 410) or higher (n = 404) doses. There were 51 (12.5%) and 49 (12.5%) primary end points in the 3- and 7-day arms, respectively (difference 0.1%, 90% confidence interval -3.8% to 3.9%) and 51 (12.6%) and 49 (12.4%) primary end points in the low- and high-dose arms, respectively (difference 0.2%, 90% confidence interval -3.7% to 4.0%), both demonstrating non-inferiority. Resolution of cough was faster in the 7-day arm than in the 3-day arm for cough (10 days vs. 12 days) (p = 0.040), with no difference in time to resolution of other symptoms. The type and frequency of adverse events and rate of colonisation by penicillin-non-susceptible pneumococci were comparable between arms.

LIMITATIONS

End-of-treatment swabs were not taken, and 28-day swabs were collected in only 53% of children. We focused on phenotypic penicillin resistance testing in pneumococci in the nasopharynx, which does not describe the global impact on the microflora. Although 21% of children did not attend the final 28-day visit, we obtained data from general practitioners for the primary end point on all but 3% of children.

CONCLUSIONS

Antibiotic retreatment, adverse events and nasopharyngeal colonisation by penicillin-non-susceptible pneumococci were similar with the higher and lower amoxicillin doses and the 3- and 7-day treatments. Time to resolution of cough and sleep disturbance was slightly longer in children taking 3 days' amoxicillin, but time to resolution of all other symptoms was similar in both arms.

FUTURE WORK

Antimicrobial resistance genotypic studies are ongoing, including whole-genome sequencing and shotgun metagenomics, to fully characterise the effect of amoxicillin dose and duration on antimicrobial resistance. The analysis of a randomised substudy comparing parental electronic and paper diary entry is also ongoing.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN76888927, EudraCT 2016-000809-36 and CTA 00316/0246/001-0006.

FUNDING

This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 25, No. 60. See the NIHR Journals Library website for further project information.

Effect of Amoxicillin Dose and Treatment Duration on the Need for Antibiotic Re-treatment in Children With Community-Acquired Pneumonia: The CAP-IT Randomized Clinical Trial

IMPORTANCE

The optimal dose and duration of oral amoxicillin for children with community-acquired pneumonia (CAP) are unclear.

OBJECTIVE

To determine whether lower-dose amoxicillin is noninferior to higher dose and whether 3-day treatment is noninferior to 7 days.

DESIGN, SETTING, AND PARTICIPANTS

Multicenter, randomized, 2 × 2 factorial noninferiority trial enrolling 824 children, aged 6 months and older, with clinically diagnosed CAP, treated with amoxicillin on discharge from emergency departments and inpatient wards of 28 hospitals in the UK and 1 in Ireland between February 2017 and April 2019, with last trial visit on May 21, 2019.

INTERVENTIONS

Children were randomized 1:1 to receive oral amoxicillin at a lower dose (35-50 mg/kg/d; n = 410) or higher dose (70-90 mg/kg/d; n = 404), for a shorter duration (3 days; n = 413) or a longer duration (7 days; n = 401).

MAIN OUTCOMES AND MEASURES

The primary outcome was clinically indicated antibiotic re-treatment for respiratory infection within 28 days after randomization. The noninferiority margin was 8%. Secondary outcomes included severity/duration of 9 parent-reported CAP symptoms, 3 antibiotic-related adverse events, and phenotypic resistance in colonizing Streptococcus pneumoniae isolates.

RESULTS

Of 824 participants randomized into 1 of the 4 groups, 814 received at least 1 dose of trial medication (median [IQR] age, 2.5 years [1.6-2.7]; 421 [52%] males and 393 [48%] females), and the primary outcome was available for 789 (97%). For lower vs higher dose, the primary outcome occurred in 12.6% with lower dose vs 12.4% with higher dose (difference, 0.2% [1-sided 95% CI -∞ to 4.0%]), and in 12.5% with 3-day treatment vs 12.5% with 7-day treatment (difference, 0.1% [1-sided 95% CI -∞ to 3.9]). Both groups demonstrated noninferiority with no significant interaction between dose and duration (P = .63). Of the 14 prespecified secondary end points, the only significant differences were 3-day vs 7-day treatment for cough duration (median 12 days vs 10 days; hazard ratio [HR], 1.2 [95% CI, 1.0 to 1.4]; P = .04) and sleep disturbed by cough (median, 4 days vs 4 days; HR, 1.2 [95% CI, 1.0 to 1.4]; P = .03). Among the subgroup of children with severe CAP, the primary end point occurred in 17.3% of lower-dose recipients vs 13.5% of higher-dose recipients (difference, 3.8% [1-sided 95% CI, -∞ to10%]; P value for interaction = .18) and in 16.0% with 3-day treatment vs 14.8% with 7-day treatment (difference, 1.2% [1-sided 95% CI, -∞ to 7.4%]; P value for interaction = .73).

CONCLUSIONS AND RELEVANCE

Among children with CAP discharged from an emergency department or hospital ward (within 48 hours), lower-dose outpatient oral amoxicillin was noninferior to higher dose, and 3-day duration was noninferior to 7 days, with regard to need for antibiotic re-treatment. However, disease severity, treatment setting, prior antibiotics received, and acceptability of the noninferiority margin require consideration when interpreting the findings.

TRIAL REGISTRATION

ISRCTN Identifier: ISRCTN76888927.

The Effect of Haematocrit on Measurement of the Mid-Infrared Refractive Index of Plasma in Whole Blood

Recent advances suggest that miniaturised mid-infrared (MIR) devices could replace more time-consuming, laboratory-based techniques for clinical diagnostics. This work uses Fourier transform infrared spectroscopy to show that the MIR complex refractive index of whole blood varies across a range of haematocrit. This indicates that the use of an evanescent measurement is not sufficient to optically exclude the cellular content of blood in the MIR, as previously assumed. Here, spectral refractive index data is presented in two ways. First, it is given as whole blood with varying haematocrit. Second, it is given as the percentage error that haematocrit introduces to plasma. The maximum error in the effective plasma refractive index due to the haematocrit of healthy adults was 0.25% for the real part n and 11% for the imaginary part k. This implies that calibration measurements of haematocrit can be used to account for errors introduced by the cellular content, enabling plasma spectra and analyte concentrations to be indirectly calculated from a whole blood sample. This methodological advance is of clinical importance as plasma concentration of analytes such as drugs can be determined using MIR without the preprocessing of whole blood.

RSV: perspectives to strengthen the need for protection in all infants

Respiratory syncytial virus (RSV)-the most common viral cause of bronchiolitis-is a significant cause of serious illness among young children between the ages of 0-5 years and is especially concerning in the first year of life. Globally, RSV is a common cause of childhood acute lower respiratory illness (ALRI) and a major cause of hospital admissions in young children and infants and represents a substantial burden for health-care systems. This burden is strongly felt as there are currently no effective preventative options that are available for all infants. However, a renaissance in RSV prevention strategies is unfolding, with several new prophylactic options such as monoclonal antibodies and maternal vaccinations that are soon to be available. A key concern is that health decision makers and systems may not be ready to take full advantage of forthcoming technological innovations. A multi-stakeholder approach is necessary to bridge data gaps to fully utilise upcoming options. Knowledge must be made available at multiple levels to ensure that parents and doctors are aware of preventative options, but also to ensure that stakeholders and policymakers are given the necessary information to best advise implementation strategies.

Antibiotics for lower respiratory tract infection in children presenting in primary care in England (ARTIC PC): a double-blind, randomised, placebo-controlled trial

BACKGROUND

Antibiotic resistance is a global public health threat. Antibiotics are very commonly prescribed for children presenting with uncomplicated lower respiratory tract infections (LRTIs), but there is little evidence from randomised controlled trials of the effectiveness of antibiotics, both overall or among key clinical subgroups. In ARTIC PC, we assessed whether amoxicillin reduces the duration of moderately bad symptoms in children presenting with uncomplicated (non-pneumonic) LRTI in primary care, overall and in key clinical subgroups.

METHODS

ARTIC PC was a double-blind, randomised, placebo-controlled trial done at 56 general practices in England. Eligible children were those aged 6 months to 12 years presenting in primary care with acute uncomplicated LRTI judged to be infective in origin, where pneumonia was not suspected clinically, with symptoms for less than 21 days. Patients were randomly assigned in a 1:1 ratio to receive amoxicillin 50 mg/kg per day or placebo oral suspension, in three divided doses orally for 7 days. Patients and investigators were masked to treatment assignment. The primary outcome was the duration of symptoms rated moderately bad or worse (measured using a validated diary) for up to 28 days or until symptoms resolved. The primary outcome and safety were assessed in the intention-to-treat population. The trial is registered with the ISRCTN Registry (ISRCTN79914298).

FINDINGS

Between Nov 9, 2016, and March 17, 2020, 432 children (not including six who withdrew permission for use of their data after randomisation) were randomly assigned to the antibiotics group (n=221) or the placebo group (n=211). Complete data for symptom duration were available for 317 (73%) patients; missing data were imputed for the primary analysis. Median durations of moderately bad or worse symptoms were similar between the groups (5 days [IQR 4-11] in the antibiotics group vs 6 days [4-15] in the placebo group; hazard ratio [HR] 1·13 [95% CI 0·90-1·42]). No differences were seen for the primary outcome between the treatment groups in the five prespecified clinical subgroups (patients with chest signs, fever, physician rating of unwell, sputum or chest rattle, and short of breath). Estimates from complete-case analysis and a per-protocol analysis were similar to the imputed data analysis.

INTERPRETATION

Amoxicillin for uncomplicated chest infections in children is unlikely to be clinically effective either overall or for key subgroups in whom antibiotics are commonly prescribed. Unless pneumonia is suspected, clinicians should provide safety-netting advice but not prescribe antibiotics for most children presenting with chest infections.

FUNDING

National Institute for Health Research.

Powered Respirators Are Effective, Sustainable, and Cost-Effective Personal Protective Equipment for SARS-CoV-2

Objectives: The provision of high-quality personal protective equipment (PPE) has been a critical challenge during the COVID-19 pandemic. We evaluated an alternative strategy, mass deployment of a powered air-purifying respirator (PeRSo), in a large university hospital. Methods: We performed prospective user feedback via questionnaires sent to healthcare workers (HCWs) issued PeRSos, economic analysis, and evaluated the real-world impact. Results: Where paired responses were available, PeRSo was preferred over droplet precautions for comfort, patient response, overall experience, and subjective feeling of safety. For all responses, more participants reported the overall experience being rated "Very good" more frequently for PeRSo. The primary limitation identified was impairment of hearing. Economic simulation exercises revealed that the adoption of PeRSo within ICU is associated with net cost savings in the majority of scenarios and savings increased progressively with greater ITU occupancy. In evaluation during the second UK wave, over 3,600 respirators were deployed, all requested by staff, which were associated with a low staff absence relative to most comparator hospitals. Conclusions: Health services should consider a widespread implementation of powered reusable respirators as a safe and sustainable solution for the protection of HCWs as SARS-CoV-2 becomes an endemic viral illness.