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.

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.

Assessing the Response of Biomarkers to Anti-Inflammatory Medications in PIMS-TS by Longitudinal Multilevel Modeling: Real-World Data from a UK Tertiary Center

Background: Pediatric inflammatory multisystem syndrome temporarily associated with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection (PIMS-TS) is an acute complication of previous SARS-CoV-2 exposure. The relationship between inflammatory markers and anti-inflammatory medication in PIMS-TS is unknown. We retrospectively investigated the relationship between demographics, biomarkers, treatment, and length of stay (LOS) in this novel disease. Methods: We reviewed the case notes and blood tests of all patients who met the Royal College of Paediatrics and Child Health diagnostic criteria for PIMS-TS at a large tertiary center in the United Kingdom. Biomarker trajectories were modeled using log linear mixed effects, and factors affecting LOS in hospital were evaluated using multiple regression. Results: Between March 2020 and May 2022, a total of 56 patients attended Sheffield Children's Hospital with PIMS-TS, 70% male. Mean age was 7.4 ± 3.7 years and mean LOS 8.7 ± 4.5 days with 50% requiring intensive care and 20% requiring inotropes. Older males had shorter LOS than younger males (P = 0.04), not seen in females. Treatment included intravenous glucocorticoids in 93%, intravenous immunoglobulins (IVIG) in 77%, Anakinra in 11%, and infliximab in 1.8%. Biomarkers correlated poorly with trajectories that peaked at different times. C-reactive protein peaked first after median 1.3 days postadmission; while LFT's and neutrophils peaked after 3 days. Age had a large effect on some biomarkers, with older children having larger troponin and ferritin, and lower lymphocytes and platelets. Cumulative dose of glucocorticoids and IVIG had a statistically significant effect on some biomarkers, but effect size was small. Conclusions: The heterogenous nature of PIMS-TS highlights the importance of a multidisciplinary approach. Worse inflammatory markers in older children within our cohort may be an indication of a different disease process occurring at different ages. Future work to investigate the association between age and troponin and ferritin in hyperinflammatory states is warranted.

A National Survey of Hereditary Angioedema and Acquired C1 Inhibitor Deficiency in the United Kingdom

BACKGROUND

Detailed demographic data on people with hereditary angioedema (HAE) and acquired C1 inhibitor deficiency in the United Kingdom are relatively limited. Better demographic data would be beneficial in planning service provision, identifying areas of improvement, and improving care.

OBJECTIVE

To obtain more accurate data on the demographics of HAE and acquired C1 inhibitor deficiency in the United Kingdom, including treatment modalities and services available to patients.

METHODS

A survey was distributed to all centers in the United Kingdom that look after patients with HAE and acquired C1 inhibitor deficiency to collect these data.

RESULTS

The survey identified 1152 patients with HAE-1/2 (58% female and 92% type 1), 22 patients with HAE with normal C1 inhibitor, and 91 patients with acquired C1 inhibitor deficiency. Data were provided by 37 centers across the United Kingdom. This gives a minimum prevalence of 1:59,000 for HAE-1/2 and 1:734,000 for acquired C1 inhibitor deficiency in the United Kingdom. A total of 45% of patients with HAE were on long-term prophylaxis (LTP) with the most used medication being danazol (55% of all patients on LTP). Eighty-two percent of patients with HAE had a home supply of acute treatment with C1 inhibitor or icatibant. A total of 45% of patients had a supply of icatibant and 56% had a supply of C1 inhibitor at home.

CONCLUSIONS

Data obtained from the survey provide useful information about the demographics and treatment modalities used in HAE and acquired C1 inhibitor deficiency in the United Kingdom. These data are useful for planning service provision and improving services for these patients.

Actin nucleators safeguard replication forks by limiting nascent strand degradation

Accurate genome replication is essential for all life and a key mechanism of disease prevention, underpinned by the ability of cells to respond to replicative stress (RS) and protect replication forks. These responses rely on the formation of Replication Protein A (RPA)-single stranded (ss) DNA complexes, yet this process remains largely uncharacterized. Here, we establish that actin nucleation-promoting factors (NPFs) associate with replication forks, promote efficient DNA replication and facilitate association of RPA with ssDNA at sites of RS. Accordingly, their loss leads to deprotection of ssDNA at perturbed forks, impaired ATR activation, global replication defects and fork collapse. Supplying an excess of RPA restores RPA foci formation and fork protection, suggesting a chaperoning role for actin nucleators (ANs) (i.e. Arp2/3, DIAPH1) and NPFs (i.e, WASp, N-WASp) in regulating RPA availability upon RS. We also discover that β-actin interacts with RPA directly in vitro, and in vivo a hyper-depolymerizing β-actin mutant displays a heightened association with RPA and the same dysfunctional replication phenotypes as loss of ANs/NPFs, which contrasts with the phenotype of a hyper-polymerizing β-actin mutant. Thus, we identify components of actin polymerization pathways that are essential for preventing ectopic nucleolytic degradation of perturbed forks by modulating RPA activity.

Actin nucleators safeguard replication forks by limiting nascent strand degradation

Accurate genome replication is essential for all life and a key mechanism of disease prevention, underpinned by the ability of cells to respond to replicative stress (RS) and protect replication forks. These responses rely on the formation of Replication Protein A (RPA)-single stranded (ss) DNA complexes, yet this process remains largely uncharacterized. Here we establish that actin nucleation-promoting factors (NPFs) associate with replication forks, promote efficient DNA replication and facilitate association of RPA with ssDNA at sites of RS. Accordingly, their loss leads to deprotection of ssDNA at perturbed forks, impaired ATR activation, global replication defects and fork collapse. Supplying an excess of RPA restores RPA foci formation and fork protection, suggesting a chaperoning role for actin nucleators (ANs) (i.e., Arp2/3, DIAPH1) and NPFs (i.e, WASp, N-WASp) in regulating RPA availability upon RS. We also discover that β-actin interacts with RPA directly in vitro , and in vivo a hyper-depolymerizing β-actin mutant displays a heightened association with RPA and the same dysfunctional replication phenotypes as loss of ANs/NPFs, which contrasts with the phenotype of a hyper-polymerizing β-actin mutant. Thus, we identify components of actin polymerization pathways that are essential for preventing ectopic nucleolytic degradation of perturbed forks by modulating RPA activity.

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.

Parental experience of prophylactic antibiotics

BACKGROUND AND OBJECTIVES

Long-term prophylactic antibiotics are often used to prevent bacterial infections. However, supporting evidence for this is not always robust. Including parents in decisions relating to medication is key to medicines optimisation. Parental concern regarding medication is a major determinant of poor adherence. This study explores parental experiences of having a child prescribed prophylactic antibiotics and how that affects their antibiotic use behaviour.

METHODS

We conducted a prospective, single-centre, exploratory, qualitative study at Sheffield Children's Hospital. Through 15 interviews, involving 18 participants, we explored parental 'lived experiences' and attitudes towards azithromycin prophylaxis prescribed for various respiratory conditions. Thematic analysis was conducted.

RESULTS

The overriding factor influencing parental decisions about the uptake of antibiotic prophylaxis is wanting their child to be well now. The main concern voiced by parents is that of antibiotic resistance given their children are high users of antibiotics. This is however seen as a problem for the future, not the present. Preparing families adequately helps prevent practical difficulties relating to medication. Facilitating 'normalisation' of prophylaxis through daily routines and minimising disruption to the family environment may reduce parental anxiety, promote adherence and result in easing of potential restrictions to the child's daily activities.

CONCLUSION

Grounded in our deeper understanding, we propose a behavioural model that describes phases parents go through while having a child on prophylactic antibiotics. Time invested in holistically addressing the parental experience and having an awareness of potential issues parents face, may facilitate medication adherence, reduce anxieties and improve doctor-parent relationships.

Tuberculosis Disease in Children and Adolescents on Therapy With Antitumor Necrosis Factor-ɑ Agents: A Collaborative, Multicenter Paediatric Tuberculosis Network European Trials Group (ptbnet) Study

BACKGROUND

In adults, anti-tumor necrosis factor-α (TNF-α) therapy is associated with progression of latent tuberculosis (TB) infection (LTBI) to TB disease, but pediatric data are limited.

METHODS

Retrospective multicenter study within the Paediatric Tuberculosis Network European Trials Group, capturing patients <18 years who developed TB disease during anti-TNF-α therapy.

RESULTS

Sixty-six tertiary healthcare institutions providing care for children with TB participated. Nineteen cases were identified: Crohn's disease (n = 8; 42%) and juvenile idiopathic arthritis (n = 6; 32%) were the commonest underlying conditions. Immune-based TB screening (tuberculin skin test and/or interferon-γ release assay) was performed in 15 patients before commencing anti-TNF-α therapy but only identified 1 LTBI case; 13 patients were already receiving immunosuppressants at the time of screening. The median interval between starting anti-TNF-α therapy and TB diagnosis was 13.1 (IQR, 7.1-20.3) months. All cases presented with severe disease, predominantly miliary TB (n = 14; 78%). One case was diagnosed postmortem. TB was microbiologically confirmed in 15 cases (79%). The median duration of anti-TB treatment was 50 (IQR, 46-66) weeks. Five of 15 (33%) cases who had completed TB treatment had long-term sequelae.

CONCLUSIONS

LTBI screening is frequently false-negative in this patient population, likely due to immunosuppressants impairing test performance. Therefore, patients with immune-mediated diseases should be screened for LTBI at the point of diagnosis, before commencing immunosuppressive medication. Children on anti-TNF-α therapy are prone to severe TB disease and significant long-term morbidity. Those observations underscore the need for robust LTBI screening programs in this high-risk patient population, even in low-TB-prevalence settings.

Loss of the interleukin-6 receptor causes immunodeficiency, atopy, and abnormal inflammatory responses

IL-6 excess is central to the pathogenesis of multiple inflammatory conditions and is targeted in clinical practice by immunotherapy that blocks the IL-6 receptor encoded by IL6R We describe two patients with homozygous mutations in IL6R who presented with recurrent infections, abnormal acute-phase responses, elevated IgE, eczema, and eosinophilia. This study identifies a novel primary immunodeficiency, clarifying the contribution of IL-6 to the phenotype of patients with mutations in IL6ST, STAT3, and ZNF341, genes encoding different components of the IL-6 signaling pathway, and alerts us to the potential toxicity of drugs targeting the IL-6R.

Compound heterozygous variants in NBAS as a cause of atypical osteogenesis imperfecta

BACKGROUND

Osteogenesis imperfecta (OI), the commonest inherited bone fragility disorder, affects 1 in 15,000 live births resulting in frequent fractures and reduced mobility, with significant impact on quality of life. Early diagnosis is important, as therapeutic advances can lead to improved clinical outcome and patient benefit.

REPORT

Whole exome sequencing in patients with OI identified, in two patients with a multi-system phenotype, compound heterozygous variants in NBAS (neuroblastoma amplified sequence). Patient 1: NBAS c.5741G>A p.(Arg1914His); c.3010C>T p.(Arg1004*) in a 10-year old boy with significant short stature, bone fragility requiring treatment with bisphosphonates, developmental delay and immunodeficiency. Patient 2: NBAS c.5741G>A p.(Arg1914His); c.2032C>T p.(Gln678*) in a 5-year old boy with similar presenting features, bone fragility, mild developmental delay, abnormal liver function tests and immunodeficiency.

DISCUSSION

Homozygous missense NBAS variants cause SOPH syndrome (short stature; optic atrophy; Pelger-Huet anomaly), the same missense variant was found in our patients on one allele and a nonsense variant in the other allele. Recent literature suggests a multi-system phenotype. In this study, patient fibroblasts have shown reduced collagen expression, compared to control cells and RNAseq studies, in bone cells show that NBAS is expressed in osteoblasts and osteocytes of rodents and primates. These findings provide proof-of-concept that NBAS mutations have mechanistic effects in bone, and that NBAS variants are a novel cause of bone fragility, which is distinguishable from 'Classical' OI.

CONCLUSIONS

Here we report on variants in NBAS, as a cause of bone fragility in humans, and expand the phenotypic spectrum associated with NBAS. We explore the mechanism underlying NBAS and the striking skeletal phenotype in our patients.

Prevalence, incidence, and associated risk factors of tuberculosis in children with HIV living in the UK and Ireland (CHIPS): a cohort study

BACKGROUND

Tuberculosis is the most common serious co-infection in people living with HIV worldwide, but little is known about its incidence in HIV-infected children living in high-resource settings with low tuberculosis prevalence. We aimed to assess the incidence and prevalence of tuberculosis in children with HIV living in the UK and Ireland to understand rates, risk factors, and outcomes of the disease in this group.

METHODS

We did an analysis of children enrolled in CHIPS, an observational multicentre cohort of children receiving HIV care in the UK and Ireland. We assessed characteristics and prevalence of tuberculosis at baseline, measured incidence of disease through the follow-up period using the CHIPS database, and calculated associated risk factors in these children with multivariable logistic and Cox regression models.

FINDINGS

Between Jan 1, 1996, to Sept 18, 2014, data for 1848 children with 14 761 years of follow-up were reported to CHIPS. 57 (3%) children were diagnosed with tuberculosis: 29 children had tuberculosis at presentation (prevalent tuberculosis) and 29 had the disease diagnosed during follow-up (incident tuberculosis), including one child with recurrent tuberculosis events. Median age at diagnosis was 9 years (IQR 5-12). 25 (43%) children had pulmonary tuberculosis, 24 (41%) had extrapulmonary tuberculosis with or without pulmonary involvement, and the remainder (n=9; 16%) had unspecified-site tuberculosis. The overall incidence rate for the follow-up period was 196 cases per 100 000 person-years (95% CI 137-283). In our multivariable model, tuberculosis at presentation was associated with more severe WHO immunological stage at baseline (odds ratio 0·25, 95% CI 0·08-0·74; p=0·0331; for none vs severe) and being born abroad (odds ratio 0·28, 0·10-0·73; p=0·0036; for UK and Ireland vs abroad). Incident tuberculosis was associated with time-updated more severe WHO immunological stage (hazard ratio 0·15, 95% CI 0·06-0·41; p=0·0056; for none vs severe) and older age at baseline (1·11, 0·47-2·63; p=0·0027; for age >10 years vs 5-9 years).

INTERPRETATION

Tuberculosis rates in HIV-infected children in the UK and Ireland were higher than those reported in the general paediatric population. Further study is warranted of tuberculosis screening and preventive treatment for children at high-risk of this disease to avoid morbidity and mortality in this population.

FUNDING

NHS England, PENTA Foundation.

Extreme growth failure is a common presentation of ligase IV deficiency

Ligase IV syndrome is a rare differential diagnosis for Nijmegen breakage syndrome owing to a shared predisposition to lympho-reticular malignancies, significant microcephaly, and radiation hypersensitivity. Only 16 cases with mutations in LIG4 have been described to date with phenotypes varying from malignancy in developmentally normal individuals, to severe combined immunodeficiency and early mortality. Here, we report the identification of biallelic truncating LIG4 mutations in 11 patients with microcephalic primordial dwarfism presenting with restricted prenatal growth and extreme postnatal global growth failure (average OFC -10.1 s.d., height -5.1 s.d.). Subsequently, most patients developed thrombocytopenia and leucopenia later in childhood and many were found to have previously unrecognized immunodeficiency following molecular diagnosis. None have yet developed malignancy, though all patients tested had cellular radiosensitivity. A genotype-phenotype correlation was also noted with position of truncating mutations corresponding to disease severity. This work extends the phenotypic spectrum associated with LIG4 mutations, establishing that extreme growth retardation with microcephaly is a common presentation of bilallelic truncating mutations. Such growth failure is therefore sufficient to consider a diagnosis of LIG4 deficiency and early recognition of such cases is important as bone marrow failure, immunodeficiency, and sometimes malignancy are long term sequelae of this disorder.

Intracranial non-Langerhans cell histiocytosis presenting as an isolated intraparenchymal lesion

Non-Langerhans cell histiocytosis in the absence of cutaneous or other organ involvement is very rare. A Caucasian boy age 3 years 11 months presented with episodes of recurrent right-side seizures over 2 weeks. Brain CT and MR imaging showed a single enhancing left frontal lobe lesion. Stereotactic biopsy was performed and histological examination showed diffuse infiltrate of macrophages with foamy cytoplasm. Four months later there was recurrence of seizure activity despite anti-epileptic medication and a repeat MR scan showed a persistent enhancing lesion in the left frontal lobe. Histological examination of the resection specimen resembled juvenile xanthogranuloma (JXG) involving the central nervous system. In the absence of skin lesions a diagnosis of non-Langerhans cell histiocytosis was made. The child made a full recovery following surgery with resolution of his symptoms.

Clinical and immunological overlap between autoimmune lymphoproliferative syndrome and common variable immunodeficiency

Autoimmune lymphoproliferative syndrome (ALPS) is mainly caused by defects in the CD95 pathway. Raised CD3+TCRαβ+CD4-CD8- double negative T cells and impaired T cell apoptosis are hallmarks of the disease. In contrast, the B cell compartment has been less well studied. We found an altered distribution of B cell subsets with raised transitional B cells and reduced marginal zone B cells, switched memory B cells and plasma blasts in most of 22 analyzed ALPS patients. Moreover, 5 out of 66 ALPS patients presented with low IgG and susceptibility to infection revealing a significant overlap between ALPS and common variable immunodeficiency (CVID). In patients presenting with lymphoproliferation, cytopenia, hypogammaglobulinemia and impaired B cell differentiation, serum biomarkers were helpful in addition to apoptosis tests for the identification of ALPS patients. Our observations may indicate a role for apoptosis defects in some diseases currently classified as CVID.

Onchocercosis mansonella co-infection presenting as a subcutaneous nodule in a child

A 11-year-old girl presented with a subcutaneous lesion on the forehead, thought to be an implantation dermoid cyst. Microscopic examination revealed an onchocercoma. Microfilariae were found in the blood indicating a co-infection with Mansonella perstans. This case demonstrates the diagnostic difficulties of a parasitic co-infection uncommonly encountered in Europe.

Capsular serotype-specific attack rates and duration of carriage of Streptococcus pneumoniae in a population of children

BACKGROUND

The relative invasiveness rates (attack rates) of Streptococcus pneumoniae of different capsular serotypes in children are not known. Estimates of capsular serotype invasiveness (designated "invasive odds ratios") that are based on cross-sectional prevalence carriage data have been published, but these estimates could be biased by variation in the duration of carriage.

METHODS

The relative attack rates of invasive pneumococci were measured using national UK surveillance data on invasive pneumococcal disease (IPD) incidence and data on incidence of pneumococcal acquisition from longitudinal studies of nasopharyngeal pneumococcal carriage.

RESULTS

We found significant differences in capsular serotype-specific attack rates. For example, capsular serotypes 4, 14, 7F, 9V, and 18C were associated with rates of >20 IPD cases/100,000 acquisitions, whereas capsular serotypes 23F, 6A, 19F, 16F, 6B, and 15B/C were associated with <10 IPD cases/100,000 acquisitions. There was an inverse relationship between duration of carriage and attack rate by capsular serotype (P<.0001). Attack rates were significantly correlated with invasive odds ratios (P<.0001).

CONCLUSIONS

The capsular serotype is a major determinant of both pneumococcal duration of carriage and attack rate. Published invasive odds ratios are a reliable and practical method of determining capsular serotype invasiveness and will be valuable for investigating and characterizing emerging capsular serotypes in the context of conjugate vaccination.

Outcome of invasive pneumococcal disease: a UK based study. Oxford Pneumococcal Surveillance Group

METHODS

The records of 106 children aged less than 5 years with invasive disease caused by Streptococcus pneumoniae were reviewed.

RESULTS

The clinical manifestations were meningitis (37%), upper respiratory tract infection (24%), pneumonia (19%), and occult bacteraemia (18%). One child died and seven had persisting neurological impairment. Five serotypes caused 83% of disease and 92% of the serotypes are included in the seven valent conjugate vaccines which are undergoing trials.

CONCLUSIONS

These data suggest that S pneumoniae infection is associated with a low case fatality rate but substantial morbidity in the UK.

Safety, immunogenicity, and induction of immunologic memory by a serogroup C meningococcal conjugate vaccine in infants: A randomized controlled trial

CONTEXT

Neisseria meningitidis is a common cause of meningitis and septicemia in infants worldwide. Whether a meningococcal C conjugate vaccine protects infants against the serogroup C strain is unknown.

OBJECTIVES

To determine whether a meningococcal C conjugate vaccine is safe and immunogenic and induces immunologic memory in infants.

DESIGN

Single-center, double-blind, randomized controlled trial in 1995 and 1996.

SETTING

Community, Oxfordshire, England.

PARTICIPANTS

One hundred eighty-two healthy infants.

INTERVENTIONS

Participants were randomly assigned to receive vaccination with 0. 5-mL doses of 1 of 2 lots of meningococcal C conjugate vaccine (groups 1 and 2; n=60 in each group) or a hepatitis B control vaccine (group 3; n=62), administered with routine immunizations at 2, 3, and 4 months of age. Approximately half of each group received meningococcal C conjugate vaccine and half received plain meningococcal polysaccharide vaccine (MPS) at 12 months of age.

MAIN OUTCOME MEASURES

Serum antibodies to meningococcal C polysaccharide, assayed by enzyme-linked immunosorbent assay, and serum bactericidal activity (SBA), at 2, 3, 4, 5, 12, and 13 months of age; local and systemic reactions, recorded for 6 days after each vaccination, compared by intervention group.

RESULTS

Meningococcal C conjugate vaccine was well tolerated. After 3 doses, children in groups 1 and 2 achieved significantly higher meningococcal C IgG geometric mean concentrations (21 and 17 U/mL, respectively, vs 0.20 U/mL; P<.001) and SBA titers (629 and 420, respectively, vs 4.1; P<. 001) than controls. At 12 months, antibody concentrations had decreased in all groups but remained significantly higher in children vaccinated with meningococcal C conjugate vaccine (SBA, 24 and 16 in groups 1 and 2, respectively, vs 4.2 in group 3; P<.001). Following vaccination with MPS at 12 months of age, SBA in the meningococcal C conjugate vaccine group was significantly higher than in controls (SBA, 789 vs 4.5; P<.001).

CONCLUSIONS

Our data indicate that meningococcal C conjugate vaccine is safe and immunogenic and results in immunologic memory when given with other routinely administered vaccines to infants at 2, 3, and 4 months of age. JAMA. 2000;283:2795-2801

Adverse effects and sero-responses to an acellular pertussis/diphtheria/tetanus vaccine when combined with Haemophilus influenzae type b vaccine in an accelerated schedule

Acellular pertussis vaccines provide protection against pertussis with few adverse effects. Differences in the reactogenicity and immunogenicity of available pertussis vaccines may be influenced by the immunisation schedule employed. We assessed responses to an acellular pertussis, diphtheria, tetanus vaccine mixed with Haemophilus influenzae type b (Hib) vaccine, (PRP-T) given at age 2, 3 and 4 months. Parents kept a symptom diary for 3 days after each immunisation. Antibodies to diphtheria, tetanus, pertussis toxin and filamentous haemagglutinin were measured by enzyme immunoassay at 2 and 5 months. Results were compared with historical controls who received a combination whole-cell pertussis, diphtheria, tetanus/PRP-T vaccine in the same schedule. A total of 262 infants were recruited, of whom 251 were fully evaluated after three doses of vaccine. Systemic and most local reactions were less frequent following the acellular combination. Fever > or = 38 degrees C was reported after only 0.6% of doses. Redness or swelling > or = 2.5 cm were unusual after the first two doses (2-5%), but rates rose to 13% after the third dose. Antibody responses to diphtheria and tetanus toxoids were lower, while those to pertussis antigens were higher, more uniform and less attenuated by pre-immunisation antibody than in infants who received the whole-cell combination. All infants achieved protective antibody titres of at least 0.1 IU/ml for diphtheria and 0.01 IU/ml for tetanus.

CONCLUSION

The acellular combination vaccine was immunogenic for diphtheria, tetanus and pertussis components and was associated with low rates of fever following immunisation.

Effect of combination with an acellular pertussis, diphtheria, tetanus vaccine on antibody response to Hib vaccine (PRP-T)

Acellular pertussis vaccines provide protection against whooping cough with few adverse effects. Their introduction to routine immunisation programmes would be facilitated by their incorporation with other routinely administered vaccines. 262 infants were immunised with an acellular pertussis vaccine containing pertussis toxin and filamentous haemagglutinin, combined with diphtheria and tetanus toxoids. This vaccine was mixed with Haemophilus influenzae type b tetanus toxoid vaccine (PRP-T) so that infants received a single injection at age 2, 3 and 4 months. One month after the third dose the geometric mean titre of Hib IgG antibody was 0.48 microgram ml-1. Eighty-two percent of infants achieved a titre of 0.15 microgram ml-1, with only 27% achieving 1.0 microgram ml-1. This combination vaccine induced low Hib antibody responses when compared to other studies in which PRP-T was mixed with acellular or whole-cell pertussis vaccines. The combined vaccine did, however, appear to prime a subset of 35 infants for response to a fourth dose of PRP-T at 13 months of age, with a rise in GMT from 0.21 microgram ml-1 to 36.6 micrograms ml-1. These data have important implications for the introduction of combination acellular pertussis vaccines.

Distinct T-cell subtypes induced with whole cell and acellular pertussis vaccines in children

Recent clinical trials have demonstrated that new generation acellular pertussis vaccines can confer protection against whooping cough. However, the mechanism of protective immunity against Bordetella pertussis infection induced by vaccination remains to be defined. We have examined cellular immune responses in children immunized with a range of acellular and whole cell pertussis vaccines. Immunization of children with a potent whole-cell vaccine induced B. pertussis-specific T cells that secreted interferon-gamma (IFN-gamma), but not interleukin-5 (IL-5). In contrast, T cells from children immunized with acellular pertussis vaccines secreted IFN-gamma and/or IL-5 following stimulation with B. pertussis antigens in vitro. These observations suggest that protective immunity conferred by whole-cell vaccines, like natural immunity, is mediated by type 1 T cells, whereas the mechanism of immune protection generated with acellular vaccines may be more heterogeneous, involving T cells that secreted type 1 and type 2 cytokines.