Nasopharyngeal microbiota in children is associated with severe asthma exacerbations

BACKGROUND

The respiratory microbiome has been associated with the etiology and disease course of asthma.

OBJECTIVE

We sought to assess the nasopharyngeal microbiota in children with a severe asthma exacerbation and their associations with medication, air quality, and viral infection.

METHODS

A cross-sectional study was performed among children aged 2 to 18 years admitted to the medium care unit (MCU; n = 84) or intensive care unit (ICU; n = 78) with an asthma exacerbation. For case-control analyses, we matched all cases aged 2 to 6 years (n = 87) to controls in a 1:2 ratio. Controls were participants of either a prospective case-control study or a longitudinal birth cohort (n = 182). The nasopharyngeal microbiota was characterized by 16S-rRNA-gene sequencing.

RESULTS

Cases showed higher Shannon diversity index (ICU and MCU combined; P = .002) and a distinct microbial community composition when compared with controls (permutational multivariate ANOVA R2 = 1.9%; P < .001). We observed significantly higher abundance of Staphylococcus and "oral" taxa, including Neisseria, Veillonella, and Streptococcus spp. and a lower abundance of Dolosigranulum pigrum, Corynebacterium, and Moraxella spp. (MaAsLin2; q < 0.25) in cases versus controls. Furthermore, Neisseria abundance was associated with more severe disease (ICU vs MCU MaAslin2, P = .03; q = 0.30). Neisseria spp. abundance was also related with fine particulate matter exposure, whereas Haemophilus and Streptococcus abundances were related with recent inhaled corticosteroid use. We observed no correlations with viral infection.

CONCLUSIONS

Our results demonstrate that children admitted with asthma exacerbations harbor a microbiome characterized by overgrowth of Staphylococcus and "oral" microbes and an underrepresentation of beneficial niche-appropriate commensals. Several of these associations may be explained by (environmental or medical) exposures, although cause-consequence relationships remain unclear and require further investigations.

Higher-valency pneumococcal conjugate vaccines in older adults, taking into account indirect effects from childhood vaccination: a cost-effectiveness study for the Netherlands

BACKGROUND

New 15- and 20-valent pneumococcal vaccines (PCV15, PCV20) are available for both children and adults, while PCV21 for adults is in development. However, their cost-effectiveness for older adults, taking into account indirect protection and serotype replacement from a switch to PCV15 and PCV20 in childhood vaccination, remains unexamined.

METHODS

We used a static model for the Netherlands to assess the cost-effectiveness of different strategies with 23-valent pneumococcal polysaccharide vaccine (PPV23), PCV15, PCV20, and PCV21 for a 65-year-old cohort from a societal perspective, over a 15-year time horizon. Childhood vaccination was varied from PCV10 to PCV13, PCV15, and PCV20. Indirect protection was assumed to reduce the incidence of vaccine serotypes in older adults by 80% (except for serotype 3, no effect), completely offset by an increase in non-vaccine serotype incidence due to serotype replacement.

RESULTS

Indirect effects from childhood vaccination reduced the cost-effectiveness of vaccination of older adults, depending on the serotype overlap between the vaccines. With PCV10, PCV13, or PCV15 in children, PCV20 was more effective and less costly for older adults than PPV23 and PCV15. PCV20 costs approximately €10,000 per quality-adjusted life year (QALY) gained compared to no pneumococcal vaccination, which falls below the conventional Dutch €20,000/QALY gained threshold. However, with PCV20 in children, PCV20 was no longer considered cost-effective for older adults, costing €22,550/QALY gained. As indirect effects progressed over time, the cost-effectiveness of PCV20 for older adults further diminished for newly vaccinated cohorts. PPV23 was more cost-effective than PCV20 for cohorts vaccinated 3 years after the switch to PCV20 in children. PCV21 offered the most QALY gains, and its cost-effectiveness was minimally affected by indirect effects due to its coverage of 11 different serotypes compared to PCV20.

CONCLUSIONS

For long-term cost-effectiveness in the Netherlands, the pneumococcal vaccine for older adults should either include invasive serotypes not covered by childhood vaccination or become more affordable than its current pricing for individual use.

Impact of age on pneumococcal colonization of the nasopharynx and oral cavity: an ecological perspective

Pneumococcal carriage studies have suggested that pneumococcal colonization in adults is largely limited to the oral cavity and oropharynx. In this study, we used total abundance-based β-diversity (dissimilarity) and β-diversity components to characterize age-related differences in pneumococcal serotype composition of respiratory samples. quantitative PCR (qPCR) was applied to detect pneumococcal serotypes in nasopharyngeal samples collected from 946 toddlers and 602 adults, saliva samples collected from a subset of 653 toddlers, and saliva and oropharyngeal samples collected from a subset of 318 adults. Bacterial culture rates from nasopharyngeal samples were used to characterize age-related differences in rates of colonizing bacteria. Dissimilarity in pneumococcal serotype composition was low among saliva and nasopharyngeal samples from children. In contrast, respiratory samples from adults exhibited high serotype dissimilarity, which predominantly consisted of abundance gradients and was associated with reduced nasopharyngeal colonization. Age-related serotype dissimilarity was high among nasopharyngeal samples and relatively low for saliva samples. Reduced nasopharyngeal colonization by pneumococcal serotypes coincided with significantly reduced Moraxella catarrhalis and Haemophilus influenzae and increased Staphylococcus aureus nasopharyngeal colonization rates among adults. Findings from this study suggest that within-host environmental conditions, utilized in the upper airways by pneumococcus and other bacteria, undergo age-related changes. It may result in a host-driven ecological succession of bacterial species colonizing the nasopharynx and lead to competitive exclusion of pneumococcus from the nasopharynx but not from the oral habitat. This explains the poor performance of nasopharyngeal samples for pneumococcal carriage among adults and indicates that in adults saliva more accurately represents the epidemiology of pneumococcal carriage than nasopharyngeal samples.

Effect of Palivizumab Prophylaxis on Respiratory Syncytial Virus Infection in Very Preterm Infants in the First Year of Life in The Netherlands

Respiratory Syncytial Virus (RSV) poses a severe threat to infants, particularly preterm infants. Palivizumab, the standard preventive prophylaxis, is primarily utilized in high-risk newborns due to its cost. This study assessed palivizumab's effectiveness in preventing RSV infections in predominantly very preterm infants during their first year of life. Serum samples from a prospective multicentre cohort study in the Netherlands were analyzed to assess RSV infection rates by measuring IgG levels against three RSV proteins: nucleoprotein, pre-fusion, and post-fusion protein. Infants were stratified based on gestational age (GA), distinguishing very preterm (≤32 weeks GA) from moderate/late preterm (>32 to ≤36 weeks GA). In very preterm infants, palivizumab prophylaxis significantly reduced infection rates (18.9% vs. 48.3% in the prophylaxis vs. non-prophylaxis group. Accounting for GA, sex, birth season, and birth weight, the prophylaxis group showed significantly lower infection odds. In infants with >32 to ≤36 weeks GA, the non-prophylaxis group (55.4%) showed infection rates similar to the non-prophylaxis ≤32-week GA group, despite higher maternal antibody levels in the moderate/late preterm infants. In conclusion, palivizumab prophylaxis significantly reduces RSV infection rates in very premature infants. Future research should explore clinical implications and reasons for non-compliance, and compare palivizumab with emerging prophylactics like nirsevimab aiming to optimize RSV prophylaxis and improve preterm infant outcomes.

Antibody deficiencies in children are associated with prematurity and a family history of infections

BACKGROUND

Recurrent respiratory tract infections (rRTIs) frequently affect young children and are associated with antibody deficiencies. We investigated the prevalence of and epidemiological risk factors associated with antibody deficiencies in young children with rRTIs and their progression over time, and linked these to prospectively measured RTI symptoms.

METHODS

We included children <7 years with rRTIs in a prospective cohort study. Patient characteristics associated with antibody deficiencies were identified using multivariable logistic regression analysis.

RESULTS

We included 146 children with a median age of 3.1 years. Daily RTI symptoms were monitored in winter in n = 73 children and repeated immunoglobulin level measurements were performed in n = 45 children. Antibody deficiency was diagnosed in 56% and associated with prematurity (OR 3.17 [1.15-10.29]) and a family history of rRTIs (OR 2.37 [1.11-5.15]). Respiratory symptoms did not differ between children with and without antibody deficiencies. During follow-up, antibody deficiency diagnosis remained unchanged in 67%, while 18% of children progressed to a more severe phenotype.

CONCLUSION

Immune maturation and genetic predisposition may lie at the basis of antibody deficiencies commonly observed in early life. Because disease severity did not differ between children with and without antibody deficiency, we suggest symptom management can be similar for all children with rRTIs.

IMPACT

An antibody deficiency was present in 56% of children <7 years with recurrent respiratory tract infections (rRTIs) in a Dutch tertiary hospital setting. Prematurity and a family history of rRTIs were associated with antibody deficiencies, suggesting that immune maturation and genetic predisposition may lie at the basis of antibody deficiencies in early life. RTI symptoms did not differ between children with and without antibody deficiency, suggesting that symptom management can be similar for all children with rRTIs, irrespective of humoral immunological deficiencies. During follow-up, 18% of children progressed to a more severe phenotype, emphasizing that early diagnosis is warranted to prevent long-term morbidity and increase quality of life.

High-resolution geospatial mapping of zero-dose and under-immunized children following Nigeria's 2021 multiple indicator cluster survey/national immunization coverage survey (MICS/NICS)

BACKGROUND

The "zero-dose" children are those without any routine vaccination or lacking the first dose of the diphtheria-tetanus-pertussis-containing vaccine. As per 2022 WHO/UNICEF estimates, globally, Nigeria has the highest number of zero-dose with over 2.3 million unvaccinated.

METHODS

We used data from the 2021 Nigeria Multiple Indicator Cluster Survey - National Immunisation Coverage Survey to identify zero-dose and under-immunized children. Geospatial modelling techniques were employed to determine the prevalence of zero-dose children and predict risk areas with under-immunized at a high resolution of 1x1 km.

RESULTS

Both zero-dose and under-immunized children are more prevalent in socially deprived groups. Univariate and multivariate Bayesian analyses showed positive correlations between the prevalence of zero-dose and under-immunized children with factors like stunting, contraceptive prevalence, and literacy. The prevalence of zero-dose and under-immunized children varies significantly by region and ethnicity, with higher rates observed in the country's northern parts. Significant heterogeneity in the distribution of under-vaccinated children was observed.

CONCLUSIONS

Nigeria needs to enhance its immunization system and coverage. Geospatial modelling can help deliver vaccines effectively to underserved communities. By adopting this approach, countries can ensure equitable vaccine access and contribute to global vaccination objectives.

Saliva as an alternative sample type for detection of pneumococcal carriage in young children

For children, the gold standard for the detection of pneumococcal carriage is conventional culture of a nasopharyngeal swab. Saliva, however, has a history as one of the most sensitive methods for surveillance of pneumococcal colonization and has recently been shown to improve carriage detection in older age groups. Here, we compared the sensitivity of paired nasopharyngeal and saliva samples from PCV7-vaccinated 24-month-old children for pneumococcal carriage detection using conventional and molecular detection methods. Nasopharyngeal and saliva samples were collected from 288 24-month-old children during the autumn/winter, 2012/2013. All samples were first processed by conventional diagnostic culture. Next, DNA extracted from all plate growth was tested by qPCR for the presence of the pneumococcal genes piaB and lytA and a subset of serotypes. By culture, 161/288 (60 %) nasopharyngeal swabs tested positive for pneumococcus, but detection was not possible from saliva due to abundant polymicrobial growth on culture plates. By qPCR, 155/288 (54 %) culture-enriched saliva samples and 187/288 (65 %) nasopharyngeal swabs tested positive. Altogether, 219/288 (76 %) infants tested positive for pneumococcus, with qPCR-based carriage detection of culture-enriched nasopharyngeal swabs detecting significantly more carriers compared to either conventional culture (P<0.001) or qPCR detection of saliva (P=0.002). However, 32/219 (15 %) carriers were only positive in saliva, contributing significantly to the overall number of carriers detected (P=0.002). While testing nasopharyngeal swabs by qPCR proved most sensitive for pneumococcal detection in infants, saliva sampling could be considered as complementary to provide additional information on carriage and serotypes that may not be detected in the nasopharynx and may be particularly useful in longitudinal studies, requiring repeated sampling of study participants.

Maternal and neonatal antibody levels on pertussis vaccination in pregnant women on immune-modulating therapy for rheumatic disease

OBJECTIVES

While protection against pertussis following maternal tetanus-diphtheria-and-acellular-pertussis (Tdap) vaccination was demonstrated in healthy term-born infants, no evidence is available on Tdap vaccination in combination with immune-modulating therapy during pregnancy. In this pilot study, we explored whether treatment with tumour necrosis factor alpha inhibitors (TNFis) in pregnant patients with rheumatic disease interferes with Tdap vaccine responses and affects maternal anti-pertussis IgG antibody levels in newborns.

METHODS

Patients were included by a rheumatologist during pregnancy in case they received maternal Tdap vaccination in the late-second or early-third trimester of pregnancy. Blood samples were obtained from mothers during the first pregnancy trimester, 3 months after delivery and from the umbilical cord. IgG antibody levels against Tdap-included antigens were measured using a bead-based multiplex immunoassay. Findings on patients exposed to TNFis were compared with those from TNFi-unexposed patients and with data from a historical comparator study among healthy Tdap vaccinated mother-infant pairs (n=53).

RESULTS

66 patients (46 exposed and 20 unexposed to TNFIs) were enrolled. No major differences in IgG antibody levels were observed between TNFi-exposed and unexposed mothers before maternal Tdap vaccination and 3 months after delivery. In cord sera, however, antibody levels against pertussis toxin were significantly lower after TNFi-treatment (35.94 IU/mL, 95% CI 20.68 to 62.45) compared with no TNFi-treatment of mothers with rheumatic disease (94.61 IU/mL, 95% CI 48.89 to 183.07) and lower compared with a cohort of healthy mothers (125.12 IU/mL, 95% CI 90.75 to 172.50). We observed similar differences for filamentous haemagglutinin, pertactin, tetanus toxoid and diphtheria toxoid.

CONCLUSION

These preliminary data indicate no major differences in IgG antibody levels on maternal Tdap vaccination in pregnant women with or without immune-modulating treatment, although our findings suggest that TNFis during pregnancy induce lower maternal anti-pertussis-specific protective antibody levels in newborns.

16S rRNA-Based Microbiota Profiling Assists Conventional Culture Analysis of Airway Samples from Pediatric Cystic Fibrosis Patients

16S-based sequencing provides broader information on the respiratory microbial community than conventional culturing. However, it (often) lacks species- and strain-level information. To overcome this issue, we used 16S rRNA-based sequencing results from 246 nasopharyngeal samples obtained from 20 infants with cystic fibrosis (CF) and 43 healthy infants, which were all 0 to 6 months old, and compared them to both standard (blind) diagnostic culturing and a 16S-sequencing-informed "targeted" reculturing approach. Using routine culturing, we almost uniquely detected Moraxella catarrhalis, Staphylococcus aureus, and Haemophilus influenzae (42%, 38%, and 33% of samples, respectively). Using the targeted reculturing approach, we were able to reculture 47% of the top-5 operational taxonomical units (OTUs) in the sequencing profiles. In total, we identified 60 species from 30 genera with a median of 3 species per sample (range, 1 to 8). We also identified up to 10 species per identified genus. The success of reculturing the top-5 genera present from the sequencing profile depended on the genus. In the case of Corynebacterium being in the top 5, we recultured them in 79% of samples, whereas for Staphylococcus, this value was only 25%. The success of reculturing was also correlated with the relative abundance of those genera in the corresponding sequencing profile. In conclusion, revisiting samples using 16S-based sequencing profiles to guide a targeted culturing approach led to the detection of more potential pathogens per sample than conventional culturing and may therefore be useful in the identification and, consequently, treatment of bacteria considered relevant for the deterioration or exacerbation of disease in patients like those with CF. IMPORTANCE Early and effective treatment of pulmonary infections in cystic fibrosis is vital to prevent chronic lung damage. Although microbial diagnostics and treatment decisions are still based on conventional culture methods, research is gradually focusing more on microbiome and metagenomic-based approaches. This study compared the results of both methods and proposed a way to combine the best of both worlds. Many species can relatively easily be recultured based on the 16S-based sequencing profile, and it provides more in-depth information about the microbial composition of a sample than that obtained through routine (blind) diagnostic culturing. Still, well-known pathogens can be missed by both routine diagnostic culture methods as well as by targeted reculture methods, sometimes even when they are highly abundant, which may be a consequence of either sample storage conditions or antibiotic treatment at the time of sampling.

Meningococcal ACWY conjugate vaccine immunogenicity and safety in adolescents with juvenile idiopathic arthritis and inflammatory bowel disease: A prospective observational cohort study

BACKGROUND

Immunogenicity to meningococcal serogroup ACWY (MenACWY) conjugate vaccine has not been studied in immunocompromised minors with juvenile idiopathic arthritis (JIA) or inflammatory bowel disease (IBD). We determined immunogenicity of a MenACWY-TT vaccine in JIA and IBD patients at adolescent age and compared results to data from aged-matched healthy controls (HCs).

METHODS

We performed a prospective observational cohort study in JIA and IBD patients (14-18 years old), who received a MenACWY vaccination during a nationwide catch-up campaign (2018-2019) in the Netherlands. Primary aim was to compare MenACWY polysaccharide-specific serum IgG geometric mean concentrations (GMCs) in patients with HCs and secondary between patients with or without anti-TNF therapy. GMCs were determined before and 3-6, 12, and 24 months postvaccination and compared with data from HCs at baseline and 12 months postvaccination. Serum bactericidal antibody (SBA) titers were determined in a subset of patients at 12 months postvaccination.

RESULTS

We included 226 JIA and IBD patients (66 % and 34 % respectively). GMCs were lower for MenA and MenW (GMC ratio 0·24 [0·17-0·34] and 0·16 [0·10-0·26] respectively, p < 0·01) in patients compared to HCs at 12 months postvaccination. Anti-TNF users had lower MenACWY GMCs postvaccination compared with those without anti-TNF (p < 0·01). The proportion protected (SBA ≥ 8) for MenW was reduced in anti-TNF users (76 % versus 92 % in non-anti-TNF and 100 % in HCs, p < 0.01).

CONCLUSION

The MenACWY conjugate vaccine was immunogenic in the vast majority of JIA and IBD patients at adolescent age, but seroprotection was lower in patients using anti-TNF agents. Therefore, an extra booster MenACWY vaccination should be considered.

The burden of invasive meningococcal disease in the Netherlands, 2011-2020

INTRODUCTION

Representative information on disease course and outcome of invasive meningococcal disease (IMD) is important because of the shift in meningococcal epidemiology that recently occurred in the Netherlands. With this study, we update earlier research on the burden of IMD in the Netherlands.

MATERIAL AND METHODS

We performed a retrospective study using Dutch surveillance data on IMD from July 2011 to May 2020. Clinical information was collected from hospital records. The effect of age, serogroup, and clinical manifestation on disease course and outcome was assessed in multivariable logistic regression analyses. Grouping of infecting isolates was performed by Ouchterlony gel diffusion or by PCR.

RESULTS

Clinical information was collected for 278 IMD cases of which the majority had IMD-B (55%), followed by IMD-W (27%), IMD-Y (13%), and IMD-C (5%). Most patients presented with meningitis (32%) or sepsis (30%). Hospitalisation for ≥ 10 days was most frequent among 24-64 year olds (67%). ICU admission was highest among 24-64 year olds (60%), and in case of sepsis (70%), or sepsis plus meningitis (61%). Sequelae at discharge was lower for patients with mild meningococcaemia compared to patients with sepsis plus meningitis (OR: 0.19, 95% CI: 0.07-0.51). The overall case fatality rate was 7%, and was highest for IMD-Y (14%) and IMD-W (13%) patients.

CONCLUSIONS

IMD remains a disease with high morbidity and mortality. Sepsis (with or without meningitis) is associated with a more severe disease course and outcome compared to other clinical manifestations. The high disease burden can be partly prevented by meningococcal vaccination.

Mother-to-infant microbiota transmission and infant microbiota development across multiple body sites

Early-life microbiota seeding and subsequent development is crucial to future health. Cesarean-section (CS) birth, as opposed to vaginal delivery, affects early mother-to-infant transmission of microbes. Here, we assess mother-to-infant microbiota seeding and early-life microbiota development across six maternal and four infant niches over the first 30 days of life in 120 mother-infant pairs. Across all infants, we estimate that on average 58.5% of the infant microbiota composition can be attributed to any of the maternal source communities. All maternal source communities seed multiple infant niches. We identify shared and niche-specific host/environmental factors shaping the infant microbiota. In CS-born infants, we report reduced seeding of infant fecal microbiota by maternal fecal microbes, whereas colonization with breastmilk microbiota is increased when compared with vaginally born infants. Therefore, our data suggest auxiliary routes of mother-to-infant microbial seeding, which may compensate for one another, ensuring that essential microbes/microbial functions are transferred irrespective of disrupted transmission routes.

Effectiveness of analgesic ear drops as add-on treatment to oral analgesics in children with acute otitis media: study protocol of the OPTIMA pragmatic randomised controlled trial

INTRODUCTION

Ear pain is the most prominent symptom of childhood acute otitis media (AOM). To control the pain and reduce reliance on antibiotics, evidence of effectiveness for alternative interventions is urgently needed. This trial aims to investigate whether analgesic ear drops added to usual care provide superior ear pain relief over usual care alone in children presenting to primary care with AOM.

METHODS AND ANALYSIS

This is a pragmatic, two-arm, individually randomised, open, superiority trial with cost-effectiveness analysis and nested mixed-methods process evaluation in general practices in the Netherlands. We aim to recruit 300 children aged 1-6 years with a general practitioner (GP) diagnosis of AOM and ear pain. Children will be randomly allocated (ratio 1:1) to either (1) lidocaine hydrochloride 5 mg/g ear drops (Otalgan) one to two drops up to six times daily for a maximum of 7 days in addition to usual care (oral analgesics, with/without antibiotics); or (2) usual care. Parents will complete a symptom diary for 4 weeks as well as generic and disease-specific quality of life questionnaires at baseline and 4 weeks. The primary outcome is the parent-reported ear pain score (0-10) over the first 3 days. Secondary outcomes include proportion of children consuming antibiotics, oral analgesic use and overall symptom burden in the first 7 days; number of days with ear pain, number of GP reconsultations and subsequent antibiotic prescribing, adverse events, complications of AOM and cost-effectiveness during 4-week follow-up; generic and disease-specific quality of life at 4 weeks; parents' and GPs' views and experiences with treatment acceptability, usability and satisfaction.

ETHICS AND DISSEMINATION

The Medical Research Ethics Committee Utrecht, the Netherlands, has approved the protocol (21-447/G-D). All parents/guardians of participants will provide written informed consent. Study results will be submitted for publication in peer-reviewed medical journals and presented at relevant (inter)national scientific meetings.

TRIAL REGISTRATION

The Netherlands Trial Register: NL9500; date of registration: 28 May 2021. At the time of publication of the study protocol paper, we were unable to make any amendments to the trial registration record in the Netherlands Trial Register. The addition of a data sharing plan was required to adhere to the International Committee of Medical Journal Editors guidelines. The trial was therefore reregistered in ClinicalTrials.gov (NCT05651633; date of registration: 15 December 2022). This second registration is for modification purposes only and the Netherlands Trial Register record (NL9500) should be regarded as the primary trial registration.

Reactogenicity and safety of second trimester maternal tetanus, diphtheria and acellular pertussis vaccination in the Netherlands

BACKGROUND

Maternal tetanus-diphtheria-and-acellular-pertussis (Tdap) vaccination is offered to all pregnant women during their second trimester in the Netherlands since December 2019. We assessed second trimester Tdap vaccination reactogenicity and compared with third trimester data from a similar study. For safety assessment, adverse pregnancy outcomes were compared with national data from 2018, before Tdap vaccine-introduction.

METHODS

Pregnant women were included between August 2019-December 2021 and received Tdap vaccination between 20 and 24w gestational age (GA). Participants completed a questionnaire on solicited local reactions and systemic adverse events (AEs) within one week after vaccination. Results were compared with historical data on reactogenicity from women vaccinated between 30 and 33w GA (n = 58). Regarding safety-related outcomes, each participant was matched to four unvaccinated pregnant women from the Dutch Perinatal Registry, based on living area, parity and age.

RESULTS

Among 723 participants who completed the questionnaire, 488 (67.5 %) experienced ≥ 1 local reaction with pain at the injection site as most reported reaction (62.3 %), and 460 (63.6 %) experienced ≥ 1 systemic AE with stiffness in muscles/joints (38.9 %), fatigue (28.9 %), headache (14.5 %) and common cold-like symptoms (11.0 %) most frequently reported. 4 women (0.6 %) reported fever (≥38.0˚C). Symptoms were considered mild and transient within days. No difference in AEs were found between vaccination at 20-24w versus 30-33w GA. 723 participants were matched to 2,424 unvaccinated pregnant women with no increased rates of premature labor, small-for-gestational-age, or other adverse pregnancy outcomes.

CONCLUSIONS

Second trimester maternal Tdap vaccination appears safe and well-tolerated. Comparison between second versus third trimester vaccination yielded no reactogenicity concerns.

Asymptomatic Viral Presence in Early Life Precedes Recurrence of Respiratory Tract Infections

BACKGROUND

Respiratory tract infections (RTIs) in infants are often caused by viruses. Although respiratory syncytial virus (RSV), influenza virus and human metapneumovirus (hMPV) can be considered the most pathogenic viruses in children, rhinovirus (RV) is often found in asymptomatic infants as well. Little is known about the health consequences of viral presence, especially early in life. We aimed to examine the dynamics of (a)symptomatic viral presence and relate early viral detection to susceptibility to RTIs in infants.

METHODS

In a prospective birth cohort of 117 infants, we tested 1304 nasopharyngeal samples obtained from 11 consecutive regular sampling moments, and during acute RTIs across the first year of life for 17 respiratory viruses by quantitative PCR. Associations between viral presence, viral (sub)type, viral load, viral co-detection and symptoms were tested by generalized estimating equation (GEE) models.

RESULTS

RV was the most detected virus. RV was negatively associated [GEE: adjusted odds ratio (aOR) 0.41 (95% CI 0.18-0.92)], and hMPV, RSV, parainfluenza 2 and 4 and human coronavirus HKU1 were positively associated with an acute RTI. Asymptomatic RV in early life was, however, associated with increased susceptibility to and recurrence of RTIs later in the first year of life (Kaplan-Meier survival analysis: P = 0.022).

CONCLUSIONS

Respiratory viruses, including the seasonal human coronaviruses, are often detected in infants, and are often asymptomatic. Early life RV presence is, though negatively associated with an acute RTI, associated with future susceptibility to and recurrence of RTIs. Further studies on potential ecologic or immunologic mechanisms are needed to understand these observations.

A spitting image: molecular diagnostics applied to saliva enhance detection of Streptococcus pneumoniae and pneumococcal serotype carriage

Background

Despite strong historical records on the accuracy of saliva testing, oral fluids are considered poorly suited for pneumococcal carriage detection. We evaluated an approach for carriage surveillance and vaccine studies that increases the sensitivity and specificity of pneumococcus and pneumococcal serotype detection in saliva samples.

Methods

Quantitative PCR (qPCR)-based methods were applied to detect pneumococcus and pneumococcal serotypes in 971 saliva samples collected from 653 toddlers and 318 adults. Results were compared with culture-based and qPCR-based detection in nasopharyngeal samples collected from children and in nasopharyngeal and oropharyngeal samples collected from adults. Optimal C _q cut-offs for positivity in qPCRs were determined via receiver operating characteristic curve analysis and accuracy of different approaches was assessed using a composite reference for pneumococcal and for serotype carriage based on isolation of live pneumococcus from the person or positivity of saliva samples determined with qPCR. To evaluate the inter-laboratory reproducibility of the method, 229 culture-enriched samples were tested independently in the second center.

Results

In total, 51.5% of saliva samples from children and 31.8% of saliva samples from adults were positive for pneumococcus. Detection of pneumococcus by qPCR in culture-enriched saliva exhibited enhanced sensitivity and higher agreement with a composite reference compared to diagnostic culture of nasopharyngeal samples in children (Cohen's κ: 0.69-0.79 vs. 0.61-0.73) and in adults (κ: 0.84-0.95 vs. 0.04-0.33) and culture of oropharyngeal samples in adults (κ: 0.84-0.95 vs. -0.12-0.19). Similarly, detection of serotypes with qPCR in culture-enriched saliva exhibited enhanced sensitivity and higher agreement with a composite reference compared to nasopharyngeal culture in children (κ: 0.73-0.82 vs. 0.61-0.73) and adults (κ: 0.90-0.96 vs. 0.00-0.30) and oropharyngeal culture in adults (κ: 0.90-0.96 vs. -0.13 to 0.30). However, results of qPCRs targeting serotype 4, 5, and 17F and serogroups 9, 12, and 35 were excluded due to assays' lack of specificity. We observed excellent quantitative agreement for qPCR-based detection of pneumococcus between laboratories. After exclusion of serotype/serogroup-specific assays with insufficient specificity, moderate agreement (κ 0.68, 95% CI 0.58-0.77) was observed.

Conclusion

Molecular testing of culture-enriched saliva samples improves the sensitivity of overall surveillance of pneumococcal carriage in children and adults, but limitations of qPCR-based approaches for pneumococcal serotypes carriage detection should be considered.

Longitudinal Household Assessment of Respiratory Illness in Children and Parents During the COVID-19 Pandemic

IMPORTANCE

In the early COVID-19 pandemic, SARS-CoV-2 testing was only accessible and recommended for symptomatic persons or adults. This restriction hampered assessment of the true incidence of SARS-CoV-2 infection in children as well as detailed characterization of the SARS-CoV-2 disease spectrum and how this spectrum compared with that of other common respiratory illnesses.

OBJECTIVE

To estimate the community incidence of SARS-CoV-2 infection in children and parents and to assess the symptoms and symptom severity of respiratory illness episodes involving SARS-CoV-2-positive test results relative to those with SARS-CoV-2-negative test results.

DESIGN, SETTING, AND PARTICIPANTS

This cohort study randomly selected Dutch households with at least 1 child younger than 18 years. A total of 1209 children and adults from 307 households were prospectively followed up between August 25, 2020, and July 29, 2021, covering the second and third waves of the COVID-19 pandemic. Participation included SARS-CoV-2 screening at 4- to 6-week intervals during the first 23 weeks of participation (core study period; August 25, 2020, to July 29, 2021). Participants in all households finishing the core study before July 1, 2021, were invited to participate in the extended follow-up and to actively report respiratory symptoms using an interactive app until July 1, 2021. At new onset of respiratory symptoms or a SARS-CoV-2 positive test result, a household outbreak study was initiated, which included daily symptom recording, repeated polymerase chain reaction testing (nose-throat swabs and saliva and fecal samples), and SARS-CoV-2 antibody measurement (paired dried blood spots) in all household members. Outbreaks, households, and episodes of respiratory illness were described as positive or negative depending on SARS-CoV-2 test results. Data on participant race and ethnicity were not reported because they were not uniformly collected in the original cohorts and were therefore not representative or informative.

EXPOSURES

SARS-CoV-2-positive and SARS-CoV-2-negative respiratory illness episodes.

MAIN OUTCOMES AND MEASURES

Age-stratified incidence rates, symptoms, and symptom severity for SARS-CoV-2-positive and SARS-CoV-2-negative respiratory illness episodes.

RESULTS

Among 307 households including 1209 participants (638 female [52.8%]; 403 [33.3%] aged <12 years, 179 [14.8%] aged 12-17 years, and 627 [51.9%] aged ≥18 years), 183 household outbreaks of respiratory illness were observed during the core study and extended follow-up period, of which 63 (34.4%) were SARS-CoV-2 positive (59 outbreaks [32.2%] during the core study and 4 outbreaks [2.2%] during follow-up). SARS-CoV-2 incidence was similar across all ages (0.24/person-year [PY]; 95% CI, 0.21-0.28/PY). Overall, 33 of 134 confirmed SARS-CoV-2 episodes (24.6%) were asymptomatic. The incidence of SARS-CoV-2-negative respiratory illness episodes was highest in children younger than 12 years (0.94/PY; 95% CI, 0.89-0.97/PY). When comparing SARS-CoV-2-positive vs SARS-CoV-2-negative respiratory illness episodes in children younger than 12 years, no differences were observed in number of symptoms (median [IQR], 2 [2-4] for both groups), symptom severity (median [IQR] maximum symptom severity score, 6 [4-9] vs 7 [6-13]), or symptom duration (median [IQR], 6 [5-12] days vs 8 [4-13] days). However, among adults, SARS-CoV-2-positive episodes had a significantly higher number (median [IQR], 6 [4-8] vs 3 [2-4]), severity (median [IQR] maximum symptom severity score, 15 [9-19] vs 7 [6-11]), and duration (median [IQR] 13 [8-29] days vs 5 [3-11] days; P < .001 for all comparisons) of symptoms vs SARS-CoV-2-negative episodes.

CONCLUSIONS AND RELEVANCE

In this cohort study, during the first pandemic year when mostly partial or full in-person learning occurred, the SARS-CoV-2 incidence rate in children was substantially higher than estimated from routine testing or seroprevalence data and was similar to that of adult household members. Unlike in unvaccinated adults, SARS-CoV-2 symptoms and symptom severity in children were similar to other common respiratory illnesses. These findings may prove useful when developing pediatric COVID-19 vaccine recommendations.

Memory B Cell Activation Induced by Pertussis Booster Vaccination in Four Age Groups of Three Countries

Background

Immunogenicity of acellular pertussis (aP) vaccines is conventionally assessed by measuring antibody responses but antibody concentrations wane quickly after vaccination. Memory B cells, however, are critical in sustaining long-term protection and therefore may be an important factor when assessing pertussis immunity after vaccination.

Aim

We studied pertussis specific memory B cell (re)activation induced by an aP booster vaccination in four different age groups within three countries.

Materials and methods

From a phase IV longitudinal interventional study, 268 participants across Finland, the Netherlands and the United Kingdom were included and received a 3-component pertussis booster vaccine: children (7-10y, n=53), adolescents (11-15y, n=66), young adults (20-34y, n=74), and older adults (60-70y, n=75). Memory B cells at baseline, day 28, and 1 year post-vaccination were measured by a pertussis toxin (Ptx), filamentous haemagglutinin (FHA), and pertactin (Prn) specific ELISpot assay. Antibody results measured previously were available for comparison. Furthermore, study participants were distributed into groups based on their baseline memory B cell frequencies, vaccine responses were monitored between these groups.

Results

Geometric mean (GM) memory B cell frequencies for pertussis antigens at baseline were low. At 28 days post-vaccination, these frequencies increased within each age group and were still elevated one year post-booster compared to baseline. Highest frequencies at day 28 were found within adolescents (GM: 5, 21, and 13, for Ptx, FHA and Prn, respectively) and lowest within older adults (GM: 2, 9, and 3, respectively). Moderate to strong correlations between memory B cell frequencies at day 28 and antibody concentrations at day 28 and 1 year were observed for Prn. Memory B cell frequencies &gt; 1 per 100,000 PBMCs at baseline were associated with significantly higher memory responses after 28 days and 1 year.

Conclusions

An aP booster vaccine (re)activated memory B cells in all age groups. Still elevated memory B cell frequencies after one year indicates enhanced immunological memory. However, antigen specific memory B cell activation seems weaker in older adults, which might reflect immunosenescence. Furthermore, the presence of circulating memory B cells at baseline positively affects memory B cell responses. This study was registered at www.clinicaltrialsregister.eu: No. 2016-003678-42.

It Takes Two to Tango: Combining Conventional Culture With Molecular Diagnostics Enhances Accuracy of Streptococcus pneumoniae Detection and Pneumococcal Serogroup/Serotype Determination in Carriage

Background

The specificity of molecular methods for the detection of Streptococcus pneumoniae carriage is under debate. We propose a procedure for carriage surveillance and vaccine impact studies that increases the accuracy of molecular detection of live pneumococci in polymicrobial respiratory samples.

Methods

Culture and qPCR methods were applied to detect pneumococcus and pneumococcal serotypes in 1,549 nasopharyngeal samples collected in the Netherlands (n = 972) and England (n = 577) from 946 toddlers and 603 adults, and in paired oropharyngeal samples collected exclusively from 319 Dutch adults. Samples with no live pneumococci isolated at primary diagnostic culture yet generating signal specific for pneumococcus in qPCRs were re-examined with a second, qPCR-guided culture. Optimal C_q cut-offs for positivity in qPCRs were determined via receiver operating characteristic (ROC) curve analysis using isolation of live pneumococci from the primary and qPCR-guided cultures as reference.

Results

Detection of pneumococcus and pneumococcal serotypes with qPCRs in cultured (culture-enriched) nasopharyngeal samples exhibited near-perfect agreement with conventional culture (Cohen’s kappa: 0.95). Molecular methods displayed increased sensitivity of detection for multiple serotype carriage, and implementation of qPCR-guided culturing significantly increased the proportion of nasopharyngeal and oropharyngeal samples from which live pneumococcus was recovered (p < 0.0001). For paired nasopharyngeal and oropharyngeal samples from adults none of the methods applied to a single sample type exhibited good agreement with results for primary and qPCR-guided nasopharyngeal and oropharyngeal cultures combined (Cohens kappa; 0.13–0.55). However, molecular detection of pneumococcus displayed increased sensitivity with culture-enriched oropharyngeal samples when compared with either nasopharyngeal or oropharyngeal primary cultures (p < 0.05).

Conclusion

The accuracy of pneumococcal carriage surveillance can be greatly improved by complementing conventional culture with qPCR and vice versa, by using results of conventional and qPCR-guided cultures to interpret qPCR data. The specificity of molecular methods for the detection of live pneumococci can be enhanced by incorporating statistical procedures based on ROC curve analysis. The procedure we propose for future carriage surveillance and vaccine impact studies improves detection of pneumococcal carriage in adults in particular and enhances the specificity of serotype carriage detection.

High SARS-CoV-2 household transmission rates detected by dense saliva sampling

BACKGROUND

Understanding the dynamics of SARS-CoV-2 household transmission is important for adequate infection control measures in this ongoing pandemic.

METHODS

Households were enrolled upon a PCR-confirmed index case between October and December 2020, prior to the COVID-19 vaccination program. Saliva samples were obtained by self-sampling at day 1, 3, 5, 7, 10, 14, 21, 28, 35, and 42 from study inclusion. Nasopharyngeal swabs (NPS) and oropharyngeal swabs (OPS) were collected by the research team at day 7 and capillary blood samples at day 42. Household secondary attack rate (SAR) and per-person SAR were calculated based on at least one positive saliva, NPS, OPS, or serum sample. Whole genome sequencing was performed to investigate the possibility of multiple independent SARS-CoV-2 introductions within a household.

RESULTS

Eighty-five households were included consisting of 326 (unvaccinated) individuals. Comparable numbers of secondary cases were identified by saliva (133/241; 55.2%) and serum (127/213; 59.6%). The household SAR was 88.2%. The per-person SAR was 64.3%. The majority of the secondary cases tested positive in saliva at day 1 (103/150; 68.7%). Transmission from index case to household member was not affected by age or the nature of their relationship. Phylogenetic analyses suggested a single introduction for the investigated households.

CONCLUSION

Households have a pivotal role in SARS-CoV-2 transmission. By repeated saliva self-sampling combined with NPS, OPS, and serology, we found the highest SARS-CoV-2 household transmission rates reported to date. Salivary (self-)sampling of adults and children is suitable and attractive for near real-time monitoring of SARS-CoV-2 transmission in this setting.

Effects of early-life antibiotics on the developing infant gut microbiome and resistome: a randomized trial

Broad-spectrum antibiotics for suspected early-onset neonatal sepsis (sEONS) may have pronounced effects on gut microbiome development and selection of antimicrobial resistance when administered in the first week of life, during the assembly phase of the neonatal microbiome. Here, 147 infants born at ≥36 weeks of gestational age, requiring broad-spectrum antibiotics for treatment of sEONS in their first week of life were randomized 1:1:1 to receive three commonly prescribed intravenous antibiotic combinations, namely penicillin + gentamicin, co-amoxiclav + gentamicin or amoxicillin + cefotaxime (ZEBRA study, Trial Register NL4882). Average antibiotic treatment duration was 48 hours. A subset of 80 non-antibiotic treated infants from a healthy birth cohort served as controls (MUIS study, Trial Register NL3821). Rectal swabs and/or faeces were collected before and immediately after treatment, and at 1, 4 and 12 months of life. Microbiota were characterized by 16S rRNA-based sequencing and a panel of 31 antimicrobial resistance genes was tested using targeted qPCR. Confirmatory shotgun metagenomic sequencing was executed on a subset of samples. The overall gut microbial community composition and antimicrobial resistance gene profile majorly shift directly following treatment (R²= 9.5%, adjusted p-value = 0.001 and R²= 7.5%, adjusted p-value = 0.001, respectively) and normalize over 12 months (R² = 1.1%, adjusted p-value = 0.03 and R²= 0.6%, adjusted p-value = 0.23, respectively). We find a decreased abundance of Bifidobacterium spp. and increased abundance of Klebsiella and Enterococcus spp. in the antibiotic treated infants compared to controls. Amoxicillin + cefotaxime shows the largest effects on both microbial community composition and antimicrobial resistance gene profile, whereas penicillin + gentamicin exhibits the least effects. These data suggest that the choice of empirical antibiotics is relevant for adverse ecological side-effects.

Here, in a randomized trial of 147 infants receiving distinct antibiotic regimens for early-onset neonatal sepsis, Reyman et al. characterize the gut microbiome and resistance profiles, finding differential effects of antibiotic combinations on microbial community composition and antimicrobial resistance genes.

Early-life viral infections are associated with disadvantageous immune and microbiota profiles and recurrent respiratory infections

The respiratory tract is populated by a specialized microbial ecosystem, which is seeded during and directly following birth. Perturbed development of the respiratory microbial community in early-life has been associated with higher susceptibility to respiratory tract infections (RTIs). Given a consistent gap in time between first signs of aberrant microbial maturation and the observation of the first RTIs, we hypothesized that early-life host-microbe cross-talk plays a role in this process. We therefore investigated viral presence, gene expression profiles and nasopharyngeal microbiota from birth until 12 months of age in 114 healthy infants. We show that the strongest dynamics in gene expression profiles occurred within the first days of life, mostly involving Toll-like receptor (TLR) and inflammasome signalling. These gene expression dynamics coincided with rapid microbial niche differentiation. Early asymptomatic viral infection co-occurred with stronger interferon activity, which was related to specific microbiota dynamics following, including early enrichment of Moraxella and Haemophilus spp. These microbial trajectories were in turn related to a higher number of subsequent (viral) RTIs over the first year of life. Using a multi-omic approach, we found evidence for species-specific host-microbe interactions related to consecutive susceptibility to RTIs. Although further work will be needed to confirm causality of our findings, together these data indicate that early-life viral encounters could impact subsequent host-microbe cross-talk, which is linked to later-life infections.

Seroprevalence of meningococcal ACWY antibodies across the population in the Netherlands: Two consecutive surveys in 2016/17 and 2020

BACKGROUND

Meningococcal serogroup C (MenC) vaccination was introduced for 14-month-olds in the Netherlands in 2002, alongside a mass campaign for 1-18 year-olds. Due to an outbreak of serogroup W disease, MenC vaccination was replaced for MenACWY vaccination in 2018, next to introduction of a booster at 14 years of age and a catch-up campaign for 14-18 year-olds. We assessed meningococcal ACWY antibodies across the Dutch population in 2016/17 and 2020.

METHODS

In a nationwide cross-sectional serosurvey in 2016/17, sera from participants aged 0-89 years (n = 6886) were tested for MenACWY-polysaccharide-specific (PS) serum IgG concentrations, and functional MenACWY antibody titers were determined in subsets. Moreover, longitudinal samples collected in 2020 (n = 1782) were measured for MenACWY-PS serum IgG concentrations.

RESULTS

MenC antibody levels were low, except in recently vaccinated 14-23 month-olds and individuals who were vaccinated as teenagers in 2002, with seroprevalence of 59% and 20-46%, respectively. Meningococcal AWY antibody levels were overall low both in 2016/17 and in 2020. Naturally-acquired MenW immunity was limited in 2020 despite the recent serogroup W outbreak.

CONCLUSIONS

This study demonstrates waning of MenC immunity 15 years after a mass campaign in the Netherlands. Furthermore, it highlights the lack of meningococcal AWY immunity across the population and underlines the importance of the recently introduced MenACWY (booster) vaccination.

Salivary antibody responses to ten-valent pneumococcal conjugate vaccination following two different immunization schedules in a healthy birth cohort

Pneumococcal conjugate vaccines reduce pneumococcal colonization via serotype-specific immunoglobulin G (IgG) at mucosal surfaces. The infant immunization schedule with the ten-valent pneumococcal conjugate vaccine (PCV10) changed from a 3 + 1 schedule (2-3-4-11 months) to a 2 + 1 schedule (2-4-11 months) in The Netherlands in 2013. We compared anti-pneumococcal IgG concentrations in saliva between the schedules. IgG was measured using a fluorescent bead-based multiplex immunoassay at the ages of 6 (post-primary) and 12 (post-booster) months in 51 infants receiving the 3 + 1 schedule and 68 infants receiving the 2 + 1 schedule. Post-primary IgG geometric mean concentrations (GMCs) were comparable between schedules for all vaccine serotypes. Post-booster IgG GMCs were significantly lower after the 2 + 1 schedule for serotypes 4 (p = 0.035), 7F (p = 0.048) and 23F (p = 0.0056). This study shows small differences in mucosal IgG responses between a 3 + 1 and a 2 + 1 PCV10 schedule. Future studies should establish correlates of protection against pneumococcal colonization for mucosal antibodies.

Topical or oral antibiotics for children with acute otitis media presenting with ear discharge: study protocol of a randomised controlled non-inferiority trial

BACKGROUND

Around 15%-20% of children with acute otitis media present with ear discharge due to a spontaneous tear or perforation of the eardrum (AOMd). Current guidance recommends clinicians to consider oral antibiotics as first-line treatment in this condition. The opening in the eardrum however should allow topical antibiotics to enter the middle ear directly. Local administration of antibiotics does not expose children to systemic side effects and may put less selective resistance pressure on bacteria. Evidence on the effectiveness of this approach in children with AOMd is lacking.

METHODS AND ANALYSIS

A primary care-based, open, individually randomised, controlled, non-inferiority trial. The trial aims to recruit 350 children aged 6 months to 12 years with AOMd and ear pain and/or fever. Participants will be randomised to 7 days of hydrocortisone-bacitracin-colistin eardrops five drops three times daily or amoxicillin oral suspension 50 mg/kg body weight per day, divided over three doses. Parents will keep a daily diary of AOM symptoms, adverse events and complications for 2 weeks. In addition, they will record AOM recurrences, healthcare utilisation and societal costs for 3 months. The primary outcome is the proportion of children without ear pain and fever at day 3. Secondary outcomes include ear pain and fever intensity/severity; days with ear discharge; eardrum perforation at 2 weeks; adverse events during first 2 weeks; costs; and cost effectiveness at 2 weeks and 3 months. The primary analyses will be intention-to-treat and per-protocol analyses will be conducted as well.

ETHICS AND DISSEMINATION

The medical research ethics committee Utrecht, The Netherlands has given ethical approval (17-400/G-M). Parents/guardians of participants will provide written informed consent. Study results will be submitted for publication in peer-reviewed medical journals and presented at relevant (inter)national scientific meetings.

TRIAL REGISTRATION NUMBER

The Netherlands National Trial Register; NTR6723. Date of registration: 27 November 2017.

Persistence of Antibodies to Severe Acute Respiratory Syndrome Coronavirus 2 in Relation to Symptoms in a Nationwide Prospective Study

BACKGROUND

Assessing the duration of immunity following infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a first priority to gauge the degree of protection following infection. Such knowledge is lacking, especially in the general population. Here, we studied changes in immunoglobulin isotype seropositivity and immunoglobulin G (IgG) binding strength of SARS-CoV-2-specific serum antibodies up to 7 months following onset of symptoms in a nationwide sample.

METHODS

Participants from a prospective representative serological study in the Netherlands were included based on IgG seroconversion to the spike S1 protein of SARS-CoV-2 (N = 353), with up to 3 consecutive serum samples per seroconverted participant (N = 738). Immunoglobulin M (IgM), immunoglobulin A (IgA), and IgG antibody concentrations to S1, and increase in IgG avidity in relation to time since onset of disease symptoms, were determined.

RESULTS

While SARS-CoV-2-specific IgM and IgA antibodies declined rapidly after the first month after disease onset, specific IgG was still present in 92% (95% confidence interval [CI], 89%-95%) of the participants after 7 months. The estimated 2-fold decrease of IgG antibodies was 158 days (95% CI, 136-189 days). Concentrations were sustained better in persons reporting significant symptoms compared to asymptomatic persons or those with mild upper respiratory complaints only. Similarly, avidity of IgG antibodies for symptomatic persons showed a steeper increase over time compared with persons with mild or no symptoms (P = .022).

CONCLUSIONS

SARS-CoV-2-specific IgG antibodies persist and show increasing avidity over time, indicative of underlying immune maturation. These data support development of immune memory against SARS-CoV-2, providing insight into protection of the general unvaccinated part of the population.

CLINICAL TRIALS REGISTRATION

NL8473 (the Dutch trial registry).

Detection of Neisseria meningitidis in saliva and oropharyngeal samples from college students

Carriage of Neisseria meningitidis is an accepted endpoint in monitoring meningococcal vaccines effects. We have assessed N. meningitidis and vaccine-type genogroup carriage prevalence in college students at the time of MenACWY vaccine introduction in the Netherlands, and evaluated the feasibility of saliva sampling for the surveillance of carriage. For this, paired saliva and oropharyngeal samples collected from 299 students were cultured for meningococcus. The DNA extracted from all bacterial growth was subjected to qPCRs quantifying meningococcal and genogroup-specific genes presence. Samples negative by culture yet positive for qPCR were cultured again for meningococcus. Altogether 74 (25%) of students were identified as meningococcal carrier by any method. Sixty-one students (20%) were identified as carriers with qPCR. The difference between number of qPCR-positive oropharyngeal (n = 59) and saliva (n = 52) samples was not significant (McNemar’s test, p = 0.07). Meningococci were cultured from 72 students (24%), with a significantly higher (p < 0.001) number of oropharyngeal (n = 70) compared with saliva (n = 54) samples. The prevalence of genogroups A, B, C, W, and Y was none, 9%, 1%, 1% and 6%, respectively, and 8% of students carried MenACWY vaccine-type genogroup meningococci. Saliva is easy to collect and when combined with qPCR detection can be considered for meningococcal carriage studies.

Microbial community networks across body sites are associated with susceptibility to respiratory infections in infants

Respiratory tract infections are a major cause of morbidity and mortality worldwide in young children. Concepts such as the gut-lung axis have highlighted the impact of microbial communities at distal sites in mediating disease locally. However, little is known about the extent to which microbial communities from multiple body sites are linked, and how this relates to disease susceptibility. Here, we combine 16S-based rRNA sequencing data from 112 healthy, term born infants, spanning three body sites (oral cavity, nasopharynx, gut) and the first six months of life. Using a cross-niche microbial network approach, we show that, already from the first week of life on, there is a strong association between both network structure and species essential to these structures (hub species), and consecutive susceptibility to respiratory tract infections in this cohort. Our findings underline the crucial role of cross-niche microbial connections in respiratory health.

Study protocol of the PIMPI-project, a cohort study on acceptance, tolerability and immunogenicity of second trimester maternal pertussis immunization in relation to term and preterm infants

Background

Maternal immunization confers passive immunity to the fetus by transplacental antibody transfer. Infants may be better protected against pertussis if the mother received a diphtheriae, tetanus and acellular pertussis (Tdap) vaccination in the second trimester of pregnancy compared to the third trimester. This study evaluates IgG antibody concentrations in term and preterm infants at birth and 2 months after birth after maternal Tdap-vaccination between 20⁰ and 24⁰ w of gestation vs third trimester Tdap-vaccination. Further aims are assessing the determinants that underlie acceptance of second trimester maternal Tdap-vaccination as well as the tolerability of vaccination.

Methods

This prospective cohort study consists of two parts. In the acceptance part, pregnant women complete a questionnaire on determinants that underlie acceptance of a second trimester Tdap-vaccination, which is offered subsequently between 20⁰ and 24⁰ w of gestation. Vaccinated women complete an additional questionnaire on vaccination tolerability. Vaccinated women may also participate in the immunogenicity part, in which blood is drawn from mother at delivery and from infant at birth and 2 months after birth. Women are also eligible for the immunogenicity part if they received a Tdap-vaccination between 20⁰ and 24⁰ w of gestation via the national immunization program and get hospitalized for an imminent preterm delivery. Blood sampling continues until 60 term and 60 preterm mother-infant-pairs have been included. Pertussis-specific IgG antibody concentrations are determined in serum using a fluorescent bead-based multiplex immunoassay. For term infants, non-inferiority in IgG antibody concentrations against pertussis toxin (anti-PT) will be assessed referred to a historical control group in which mothers were Tdap-vaccinated between 30⁰ and 32⁰ w of gestation. For preterm infants, non-inferiority of anti-PT IgG concentrations is referred to as 85% of infants having ≥ 20 international units/mL at 2 months after birth.

Discussion

This study investigates acceptance, tolerability and immunogenicity regarding maternal Tdap-immunization between 20⁰ and 24⁰ w of gestation. Its results provide insight into the effects of second trimester Tdap-vaccination on IgG antibody concentrations in term and preterm infants before primary infant vaccinations. Results on acceptance and tolerability guide antenatal care providers in communication with pregnant women and maintain the safety of second trimester Tdap-vaccination.

Trial registration: EU Clinical Trials Register, 2018-002976-41, retrospectively registered 24 July 2019, https://www.clinicaltrialsregister.eu/ctr-search/search?query=2018-002976-41.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12879-021-06559-w.

Respiratory Pathogen Detection in Children: Saliva as a Diagnostic Specimen

We compared pathogen detection between saliva, nasopharyngeal and oropharyngeal swabs in children with respiratory symptoms. The sensitivity in nasopharyngeal swabs was 93% (95% confidence interval [CI]: 78%-98%), in oropharyngeal swabs 79% (95% CI: 60%-90%), in saliva overall 76% (95% CI: 58%-88%) and in 18 saliva samples collected with drooling or sponges, 94% (95% CI: 74%-99%). Saliva could be a relevant specimen alternative.

Microbial and clinical factors are related to recurrence of symptoms after childhood lower respiratory tract infection

Childhood lower respiratory tract infections (LRTI) are associated with dysbiosis of the nasopharyngeal microbiota, and persistent dysbiosis following the LRTI may in turn be related to recurrent or chronic respiratory problems.

Therefore, we aimed to investigate microbial and clinical predictors of early recurrence of respiratory symptoms as well as recovery of the microbial community following hospital admission for LRTI in children.

To this end, we collected clinical data and characterised the nasopharyngeal microbiota of 154 children (4 weeks–5 years old) hospitalised for a LRTI (bronchiolitis, pneumonia, wheezing illness or mixed infection) at admission and 4–8 weeks later. Data were compared to 307 age-, sex- and time-matched healthy controls.

During follow-up, 66% of cases experienced recurrence of (mild) respiratory symptoms. In cases with recurrence of symptoms during follow-up, we found distinct nasopharyngeal microbiota at hospital admission, with higher levels of Haemophilus influenzae/haemolyticus, Prevotella oris and other gram-negatives and lower levels of Corynebacterium pseudodiphtheriticum/propinquum and Dolosigranulum pigrum compared with healthy controls. Furthermore, in cases with recurrence of respiratory symptoms, recovery of the microbiota was also diminished. Especially in cases with wheezing illness, we observed a high rate of recurrence of respiratory symptoms, as well as diminished microbiota recovery at follow-up.

Together, our results suggest a link between the nasopharyngeal microbiota composition during LRTI and early recurrence of respiratory symptoms, as well as diminished microbiota recovery after 4–8 weeks. Future studies should investigate whether (speed of) ecological recovery following childhood LRTI is associated with long-term respiratory problems.

Composition of nasopharyngeal microbiota during LRTI in children is related to recurring respiratory symptoms in the following months, and to incomplete microbiota recovery. Future research may pinpoint host and microbial predictors of clinical outcomes.https://bit.ly/3aInAwN

Trends in measles incidence and measles vaccination coverage in Nigeria, 2008-2018

INTRODUCTION

All WHO regions have set measles elimination objective for 2020. To address the specific needs of achieving measles elimination, Nigeria is using a strategy focusing on improving vaccination coverage with the first routine dose of (monovalent) measles (MCV1) at 9 months, providing measles vaccine through supplemental immunization activities (children 9-59 months), and intensified measles case-based surveillance system.

METHODS

We reviewed measles immunization coverage from population-based surveys conducted in 2010, 2013 and 2017-18. Additionally, we analyzed measles case-based surveillance reports from 2008-2018 to determine annual, regional and age-specific incidence rates.

FINDINGS

Survey results indicated low MCV1 coverage (54.0% in 2018); with lower coverage in the North (mean 45.5%). Of the 153,097 confirmed cases reported over the studied period, 85.5% (130,871) were from the North. Moreover, 70.8% (108,310) of the confirmed cases were unvaccinated. Annual measles incidence varied from a high of 320.39 per 1,000,000 population in 2013 to a low of 9.80 per 1,000,000 in 2009. The incidence rate is higher among the 9-11 months (524.0 per million) and 12-59 months (376.0 per million). Between 2008 and 2018, the incidence rate had showed geographical variation, with higher incidence in the North (70.6 per million) compare to the South (17.8 per million).

CONCLUSION

The aim of this study was to provide a descriptive analysis of measles vaccine coverage and incidence in Nigeria from 2008 to 2018 to assess country progress towards measles elimination. Although the total numbers of confirmed measles cases had decreased over the time period, measles routine coverage remains sub-optimal, and the incidence rates are critically high. The high burden of measles in the North highlight the need for region-specific interventions. The measles program relies heavily on polio resources. As the polio program winds down, strong commitments will be required to achieve elimination goals.

Invasive pneumococcal disease among adults with hematological and solid organ malignancies: A population-based cohort study

OBJECTIVES

To determine the risk of invasive pneumococcal disease (IPD) in adult cancer patients stratified by type of underlying malignancy, age, and capsular serotype and to assess herd effects of childhood pneumococcal vaccination.

METHODS

All adult IPD cases reported to the Dutch pneumococcal surveillance system between 2004 and 2016 were included in this study. IPD incidence rates (IR) stratified by subtype of malignancy were calculated per 100 000 patient-years of follow-up. Incidence rate ratios (IRR) were calculated to compare IRs between groups.

RESULTS

A total of 7167 IPD cases were included, of which 1453 were in patients with malignancies. For patients with hematological malignancies (HM) and solid organ malignancies (SOM), IRs were 482/100 000 and 79/100 000, respectively, compared with 15/100 000 in controls. The highest incidence was observed among patients with multiple myeloma, non-Hodgkin lymphoma, chronic lymphocytic leukemia, pancreatic cancer, and lung cancer (3299/100 000, 2717/100 000, 538/100 000, 559/100 000, and 393/100 000, respectively), and in patients ≥50 years old. Among HM patients, the incidence of IPD declined significantly after the implementation of infant pneumococcal vaccination (IRR 0.65, 95% confidence interval 0.51-0.84); among SOM patients, the decline was not statistically significant (IRR 0.88, 95% confidence interval 0.72-1.07).

CONCLUSIONS

The IPD disease burden in cancer patients remains high. Large differences in IPD incidence between the different types of cancer demand tailored guidance regarding pneumococcal vaccination.

Measles outbreak in complex emergency: estimating vaccine effectiveness and evaluation of the vaccination campaign in Borno State, Nigeria, 2019

BACKGROUND

From January to May 2019, large measles outbreaks affected Nigeria. Borno state was the most affected, recording 15,237 suspected cases with the state capital of Maiduguri having 1125 cases investigated and line-listed by March 2019. In Borno state, 22 of the 27 Local Government Areas (LGAs or Districts), including 37 internally displaced persons (IDPs) camps were affected. In response to the situation, an outbreak response immunization (ORI) campaign was conducted in the 13 most affected LGAs. In addition to conventional vaccination teams, special teams were deployed in security compromised areas, areas with migrants, and for nomadic and IDPs. Here we describe the outbreak and the ORI campaign. We also assess the measles-containing vaccine (MCV) coverage and vaccine effectiveness (VE) in order to quantify the population-level impact.

METHODS

We reviewed the ORI activities, and conducted an analysis of the surveillance and the outbreak investigation reports. We assessed VE of MCV by applying the screening-method. Sensitivity analyses were also conducted to assess the effect of final classification of cases on the VE of MCV. The MCV coverage was assessed by a post-campaign coverage survey after completion of the ORI through a quantitative survey in the 12 LGAs that were accessible.

RESULTS

Of the total 15,237 reported measles cases, 2002 cases were line-listed and investigated, and 737 were confirmed for measles by week 9 of 2019. Of the investigated cases 67.3% (n = 1348) were between 9 and 59 months of age. Among the 737 confirmed cases, only 9% (n = 64) stated being vaccinated with at least 1 dose of MCV. The overall VE for MCV was 98.4% (95%CI: 97.8-98.8). No significant differences were observed in the VE estimates of lab-confirmed and epi-linked cases when compared to the original estimates. The aggregated weighted vaccination coverage was 85.7% (95% CI: 79.6-90.1).

CONCLUSION

The experience in Borno demonstrates that adequate VE can be obtained in conflict-affected areas. In complex emergencies affected by measles outbreaks, health authorities may consider integration with other health strategies and the engagement of security personnel as part of the ORI activities.

Responses to an acellular pertussis booster vaccination in children, adolescents, and young and older adults: A collaborative study in Finland, the Netherlands, and the United Kingdom

Background

Pertussis can lead to serious disease and even death in infants. Older adults are more vulnerable to complications as well. In high-income countries, acellular pertussis vaccines are used for priming vaccination. In the administration of booster vaccinations to different age groups and target populations there is a substantial between-country variation. We investigated the effect of age on the response to acellular pertussis booster vaccination in three European countries.

Methods

This phase IV longitudinal intervention study performed in Finland, the Netherlands and the United Kingdom between October 2017 and January 2019 compared the vaccine responses between healthy participants of four age groups: children (7–10y), adolescents (11–15y), young adults (20–34y), and older adults (60–70y). All participants received a three-component acellular pertussis vaccine. Serum IgG and IgA antibody concentrations to pertussis antigens at day 0, 28, and 1 year were measured with a multiplex immunoassay, using pertussis toxin concentrations at day 28 as primary outcome. This trial is registered with ClinicalTrialsRegister.eu (2016–003,678–42).

Findings

Children (n = 109), adolescents (n = 121), young adults (n = 74), and older adults (n = 75) showed high IgG antibody concentrations to pertussis toxin at day 28 with GMCs of 147 (95% CI 120–181), 161 (95% CI 132–196), 103 (95% CI 80–133), and 121 IU/ml (95% CI 94–155), respectively. A significant increase in GMCs for vaccine antigens in all age groups by 28 days was found which had decreased by 1 year. Differences in patterns of IgG GMCs at 28 days and 1 year post-vaccination did not have a consistent relationship to age. In contrast, IgA antibodies for all antigens increased with age at all timepoints.

Interpretation

Acellular pertussis booster vaccination induces significant serum IgG responses to pertussis antigens across the age range which are not uniformly less in older adults. Acellular boosters could be considered for older adults to reduce the health and economic burden of pertussis.

Similar impact and replacement disease after pneumococcal conjugate vaccine introduction in hospitalised children with invasive pneumococcal disease in Europe and North America

High incidence of childhood invasive pneumococcal disease (IPD) in the US declined steeply after 7-valent pneumococcal conjugate vaccine (PCV7) introduction, outweighing reductions observed elsewhere. We re-analysed aggregate published data and compared pre- and post-PCV IPD-incidence in different countries to explore PCV impact on hospitalised and outpatient IPD separately. The proportion of hospitalised IPD cases was consistently high (>80%) in England&Wales, Finland, the Netherlands, and Quebec/Canada, but only 32% in the US before PCV introduction, increasing to 69% during the PCV era. In the US, a higher reduction in outpatient IPD incidence (94% in 2015 versus 1998-99) was observed compared to hospitalised IPD (79%); a 51% reduction in the non-PCV13-type IPD incidence among outpatient cases was estimated compared to a >2-fold increase for hospitalised cases. After stratification by hospitalization status, PCV programmes resulted in similar impact and serotype replacement in hospitalised IPD in US when compared to other countries.

The Clinical Picture and Severity of Invasive Meningococcal Disease Serogroup W Compared With Other Serogroups in the Netherlands, 2015-2018

Background

An increase in invasive meningococcal disease (IMD) serogroup W (IMD-W) cases caused by sequence type-11 clonal complex (cc11) was observed from October 2015 in the Netherlands. We compared the clinical picture and disease outcome of IMD-W cases with other serogroups, adjusting for host characteristics.

Methods

We included IMD cases reported from January 2015 to June 2018 in the Netherlands and assessed clinical manifestation and symptoms at disease onset and calculated case fatality rates (CFRs). We used logistic regression to compare clinical manifestations and mortality of IMD-W with IMD caused by meningococci serogroup B, Y, or C, adjusting for age, gender, and comorbidities.

Results

A total of 565 IMD cases were reported, of which 204 were IMD-W, 270 IMD-B, 63 IMD-Y, and 26 IMD-C. Most IMD-W isolates belonged to cc11 (93%; 175/188). Compared with other serogroups, IMD-W patients were diagnosed more often with septicemia (46%) or pneumonia (12%) and less often with meningitis (17%, P < .001). IMD-W cases presented more often with respiratory symptoms (45%, P < .001); 16% of IMD-W patients presented with diarrhea without IMD-specific symptoms (P = .061). The CFR for IMD-W was 16% (32/199, P < .001). The differences between IMD-W and other serogroups remained after adjusting for age, gender, and comorbidities.

Conclusions

The atypical presentation and severe outcome among IMD-W cases could not be explained by age, gender, and comorbidities. Almost all our IMD-W cases were caused by cc11. More research is needed to identify the bacterial factors involved in clinical presentation and severity of IMD-W cc11.

Short term impact of the COVID-19 pandemic on incidence of vaccine preventable diseases and participation in routine infant vaccinations in the Netherlands in the period March-September 2020

We aimed to assess the impact of the COVID-19 pandemic on the incidence of vaccine-preventable diseases (VPDs) and participation in the routine infant vaccination programme in the Netherlands. The incidence of various VPDs initially decreased by 75-97% after the implementation of the Dutch COVID-19 response measures. The participation in the first measles-mumps-rubella vaccination among children scheduled for vaccination in March-September 2020 initially dropped by 6-14% compared with the previous year. After catch-up vaccination, a difference in MMR1 participation of -1% to -2% still remained. Thus, the pandemic has reduced the incidence of several VPDs and has had a limited impact on the routine infant vaccination programme.

The respiratory microbiota during and following mechanical ventilation for respiratory infections in children

The lower respiratory tract (LRT) harbours distinct, dynamic low-density microbial communities, established through micro-aspiration from the upper respiratory tract (URT) [1–3]. However, during intubation and mechanical ventilation, the endotracheal tube temporarily alters the anatomical continuity between URT and LRT, and may provide a bridge for airborne microbes and a barrier for micro-aspiration. Shortly after intubation for a severe LRT infection (LRTI) in children, the microbiota of the nasopharynx and LRT were shown to be very similar [4]. However, it remains unknown how the respiratory microbial community develops while the child recovers from the infection under treatment with mechanical ventilation and antibiotics. We therefore analysed respiratory microbiota changes in children participating in our study on acute LRTIs and who were admitted to the paediatric intensive care unit (PICU) for mechanical ventilation [4].

During mechanical ventilation for an LRTI in children, the respiratory microbiota shifted from Haemophilus- and Moraxella-dominated profiles to profiles dominated by antibiotic-resistant Enterobacteriaceae, and Staphylococcus and Streptococcus species.https://bit.ly/3pGfvhQ

Impact and effectiveness of the 10-valent pneumococcal conjugate vaccine on invasive pneumococcal disease among children under 5 years of age in the Netherlands

BACKGROUND

In 2011, the 7-valent pneumococcal conjugate vaccine (PCV7) was replaced by the 10-valent vaccine (PCV10) in the Netherlands. We report on impact and effectiveness against invasive pneumococcal disease (IPD) in children aged under 5 years by switching from PCV7 to PCV10.

METHOD

We included IPD cases between 2004 and 2019 in children aged < 5 years reported via the national surveillance system. To assess the impact of the PCV10 vaccination program we compared IPD incidence 6-8 years after PCV10 introduction (2017-2019) to the two years just before the switch to PCV10 (2009-2011). We estimated vaccine effectiveness (VE) using the indirect cohort method, comparing vaccination status (at least two vaccine doses) in IPD-cases caused by PCV10 serotypes (cases) to non-PCV10 IPD cases (controls), in children eligible for PCV10.

RESULTS

The overall incidence decreased from 8.7 (n = 162) in 2009-2011 to 7.3 per 100.000 (n = 127) in 2017-2019 (Incidence rate ratio (IRR) 0.83, 95%CI: 0.66; 1.05). IPD caused by the additional serotypes included in PCV10 declined by 93% (IRR 0.07, 95%CI: 0.02; 0.23). Incidence of non-PCV10 IPD showed a non-significant increase (IRR 1.25, 95%CI: 0.96; 1.63). Among 231 IPD-cases eligible for PCV10, the overall VE was 91% (95%CI: 67; 97) and did not differ by sex or age at diagnosis. Effectiveness against non-PCV10 serotype 19A IPD was non-significant with an estimate of 28% (95%CI:-179; 81).

CONCLUSION

PCV10 is highly effective in protecting against IPD in Dutch children under 5 years with limited serotype replacement after switching from PCV7 to PCV10. We found no evidence for significant cross-protection of PCV10 against 19A serotype IPD.

Influenza-like Illness Exacerbates Pneumococcal Carriage in Older Adults

BACKGROUND

In older adults pneumococcal disease is strongly associated with respiratory viral infections, but the impact of viruses on Streptococcus pneumoniae carriage prevalence and load remains poorly understood. Here, we investigated the effects of influenza-like illness (ILI) on pneumococcal carriage in community-dwelling older adults.

METHODS

We investigated the presence of pneumococcal DNA in saliva samples collected in the 2014/2015 influenza season from 232 individuals aged ≥60 years at ILI-onset, followed by sampling 2-3 weeks and 7-9 weeks after the first sample. We also sampled 194 age-matched controls twice 2-3 weeks apart. Pneumococcal DNA was detected with quantitative-PCRs targeting piaB and lytA genes in raw and in culture-enriched saliva. Bacterial and pneumococcal abundances were determined in raw saliva with 16S and piaB quantification.

RESULTS

The prevalence of pneumococcus-positive samples was highest at onset of ILI (18% or 42/232) and lowest among controls (13% or 26/194, and 11% or 22/194, at the first and second sampling moment, respectively), though these differences were not significant. Pneumococcal carriage was associated with exposure to young children (OR:2.71, 95%CI 1.51-5.02, p<0.001), and among asymptomatic controls with presence of rhinovirus infection (OR:4.23; 95%CI 1.16-14.22, p<0.05). When compared with carriers among controls, pneumococcal absolute abundances were significantly higher at onset of ILI (p<0.01), and remained elevated beyond recovery from ILI (p<0.05). Finally, pneumococcal abundances were highest in carriage events newly-detected after ILI-onset (estimated geometric mean 1.21E -5, 95%CI 2.48E -7-2.41E -5, compared with pre-existing carriage).

CONCLUSIONS

ILI exacerbates pneumococcal colonization of the airways in older adults, and this effect persists beyond recovery from ILI.

Association of Routine Infant Vaccinations With Antibody Levels Among Preterm Infants

IMPORTANCE

The standard schedule of national immunization programs for infants may not be sufficient to protect extremely and very preterm infants.

OBJECTIVE

To evaluate the immunogenicity of routine vaccinations administered to preterm infants.

DESIGN, SETTING, AND PARTICIPANTS

A multicenter, prospective, observational cohort study of preterm infants stratified according to gestational age recruited from 8 hospitals across the Netherlands between October 2015 and October 2017, with follow-up until 12 months of age (October 2018). In total, 296 premature infants were enrolled and compared with a control group of 66 healthy term infants from a 2011 study, immunized according to the same schedule with the same vaccines.

EXPOSURES

Three primary doses of the diphtheria-tetanus toxoids-acellular pertussis-inactivated poliomyelitis-Haemophilus influenza type b-hepatitis B combination vaccine were given at 2, 3, and 4 months after birth followed by a booster at 11 months and a 10-valent pneumococcal conjugate vaccine at 2, 4, and 11 months after birth.

MAIN OUTCOMES AND MEASURES

Primary end points were (1) proportion of preterm infants who achieved IgG antibody against vaccine antigens at concentrations above the internationally defined threshold for protection after the primary series and booster dose and (2) serum IgG geometric mean concentrations after the primary series and booster vaccination. Proportions and geometric mean concentrations were compared in preterm infants and the control group of term infants.

RESULTS

Of 296 preterm infants (56.1% male; mean gestational age, 30 weeks), complete samples before vaccination, 1 month after the primary series, and 1 month after the booster were obtained from 220 preterm infants (74.3%). After the primary series, the proportion of preterm infants across all gestational age groups who achieved protective IgG antibody levels against pertussis toxin, diphtheria, tetanus and 6 of 10 pneumococcal serotypes varied between 83.0% and 100%, Haemophilus influenzae type b between 34.7% and 46.2% (40.6% among all preterm infants overall), and pneumococcal serotypes 4, 6B, 18C, and 23F between 45.8% and 75.1%. After the booster dose, protective antibody levels were achieved in more than 95% of all preterm groups, except for Haemophilus influenzae type b (88.1%). In general, geometric mean concentrations of all vaccine-induced antibodies were significantly lower in all preterm infants vs term infants, except for pertussis toxin and pneumococcal serotypes 4 and 19F after the primary series and booster vaccination.

CONCLUSIONS AND RELEVANCE

Among preterm infants, administration of routine vaccinations during the first year of life was associated with protective antibody levels against most antigens in the majority of infants after the primary series and booster, except for Haemophilus influenzae type b. However, antibody concentrations were generally lower among preterm infants compared with historical controls.

Disease burden of varicella versus other vaccine-preventable diseases before introduction of vaccination into the national immunisation programme in the Netherlands

Introduction

Estimating burden of disease (BoD) is an essential first step in the decision-making process on introducing new vaccines into national immunisation programmes (NIPs). For varicella, a common vaccine-preventable disease, BoD in the Netherlands was unknown.

Aim

To assess national varicella BoD and compare it to BoD of other vaccine-preventable diseases before their introduction in the NIP.

Methods

In this health estimates reporting study, BoD was expressed in disability-adjusted life years (DALYs) using methodology from the Burden of Communicable Diseases in Europe (BCoDE)-project. As no parameters/disease model for varicella (including herpes zoster) were available in the BCoDE toolkit, incidence, disease progression model and parameters were derived from seroprevalence, healthcare registries and published data. For most other diseases, BoD was estimated with existing BCoDE-parameters, adapted to the Netherlands if needed.

Results

In 2017, the estimated BoD of varicella in the Netherlands was 1,800 (95% uncertainty interval (UI): 1,800–1,900) DALYs. Herpes zoster mainly contributed to this BoD (1,600 DALYs; 91%), which was generally lower than the BoD of most current NIP diseases in the year before their introduction into the NIP. However, BoD for varicella was higher than for rotavirus gastroenteritis (1,100; 95%UI: 440–2,200 DALYs) and meningococcal B disease (620; 95%UI: 490–770 DALYs), two other potential NIP candidates.

Conclusions

When considering the introduction of a new vaccine in the NIP, BoD is usually estimated in isolation. The current approach assesses BoD in relation to other vaccine-preventable diseases’ BoD, which may help national advisory committees on immunisation and policymakers to set vaccination priorities.

Upper airways colonisation of Streptococcus pneumoniae in adults aged 60 years and older: A systematic review of prevalence and individual participant data meta-analysis of risk factors

•

Systematic review and meta-analysis of 18 studies and more than 6000 participants.

•

Adults over the age of 60 had a pooled prevalence of pneumococcal carriage of 9%.

•

Risk factors: contact with children, smoking and residing in a nursing home.

Background

Colonisation with Streptococcus pneumoniae can lead to invasive pneumococcal disease and pneumonia. Pneumococcal acquisition and prevalence of colonisation are high in children. In older adults, a population susceptible to pneumococcal disease, colonisation prevalence is reported to be lower, but studies are heterogeneous.

Methods

This is a systematic review and meta-analysis of prevalence of, and risk factors for, pneumococcal colonisation in adults ≥ 60 years of age (PROSPERO #42016036891). We identified peer-reviewed studies reporting the prevalence of S. pneumoniae colonisation using MEDLINE and EMBASE (until April 2016), excluding studies of acute disease. Participant-level data on risk factors were sought from each study.

Findings

Of 2202 studies screened, 29 were analysable: 18 provided participant-level data (representing 6290 participants). Prevalence of detected pneumococcal colonisation was 0–39% by conventional culture methods and 3–23% by molecular methods. In a multivariate analysis, colonisation was higher in persons from nursing facilities compared with the community (odds ratio (OR) 2•30, 95% CI 1•26–4•21 and OR 7•72, 95% CI 1•15–51•85, respectively), in those who were currently smoking (OR 1•69, 95% CI 1•12–2•53) or those who had regular contact with children (OR 1•93, 95%CI 1•27–2•93). Persons living in urban areas had significantly lower carriage prevalence (OR 0•43, 95%CI 0•27–0•70).

Interpretation

Overall prevalence of pneumococcal colonisation in older adults was higher than expected but varied by risk factors. Future studies should further explore risk factors for colonisation, to highlight targets for focussed intervention such as pneumococcal vaccination of high-risk groups.

Funding

No funding was required.

Development of the gut microbiota in early life: The impact of cystic fibrosis and antibiotic treatment

OBJECTIVES

Patients with Cystic Fibrosis (CF) suffer from pancreatic insufficiency, lipid malabsorption and gastrointestinal complaints, next to progressive pulmonary disease. Altered mucosal homoeostasis due to malfunctioning chloride channels results in an adapted microbial composition of the gastrointestinal and the respiratory tract. Additionally, antibiotic treatment has the potential to distort resident microbial communities dramatically. This study aims to investigate early life development of the gut microbial community composition of children with CF compared to healthy infants and to study the independent effects of antibiotics taking into account other clinical and lifestyle factors.

STUDY DESIGN

Faecal samples from 20 infants with CF and 45 healthy infants were collected regularly during the first 18 months of life and microbial composition was determined using 16S rRNA based sequencing.

RESULTS

We observed significant differences in the overall microbiota composition between infants with CF and healthy infants (p<0.001). Akkermansia and Anaerostipes were significantly more abundant in control infants, whereas Streptococci and E. coli were significantly more abundant in infants with CF, also after correction for several clinical factors (p<0.05). Antibiotic use in infants with CF was associated with a lower alpha diversity, a reduced abundance of Bifidobacterium and Bacteroides, and a higher abundance of Enterococcus.

CONCLUSION

Microbial development of the gut is different in infants with CF compared to healthy infants from the first months of life on, and further deviates over time, in part as a result of antibiotic treatment. The resulting dysbiosis may have significant functional consequences for the microbial ecosystem in CF patients.

Infant antibody levels following 10-valent pneumococcal-protein D conjugate and DTaP-Hib vaccinations in the first year of life after maternal Tdap vaccination: An open-label, parallel, randomised controlled trial

BACKGROUND

Maternal antibody levels after Tdap vaccination during pregnancy may affect infant primary antibody responses to pertussis, Tetanus toxoid (TT), Diphtheria toxoid (DT) vaccinations and pneumococcal vaccines with diphtheria toxin mutants like CRM197 as carrier protein.

METHODS

Mothers were recruited in an open label randomised parallel controlled trial in 2014-2016 through midwifes. They received Tdap [Boostrix] at 30-32 weeks of pregnancy (n = 58) or within 48 h after delivery (n = 60). Infants received DTaP-IPV-Hib-HepB [Infanrix Hexa] and 10-valent protein D conjugated pneumococcal conjugate vaccine (PHiD-CV10 [Synflorix]) at age 3, 5 and 11 months. We now report on infant specific IgG levels towards DT, TT, Haemophilus influenzae type b polyribosylribitol phosphate (Hib PRP) and PHiD-CV10 before and after primary- and booster vaccination as secondary study endpoints; pertussis antibodies were the primary endpoint of the study. This trial is registered in clinicaltrialsregister.eu (EudraCT 2012-004006-9) and trialregister.nl (NTR number NTR4314).

FINDINGS

Post primary vaccinations, antibody levels to DT, but not TT, were significantly lower after Tdap vaccination during pregnancy compared to controls (GMC ratio 0.4, 95% CI 0.3-0.6 and 0.9, 95% CI 0.6-1.2, respectively). Antibodies to serotype 19F were significantly lower in the maternal Tdap group, whereas there were no differences in antibody levels to Hib PRP and the other 9 pneumococcal serotypes. Post booster vaccinations, no significant differences were observed, except for DT.

INTERPRETATION

Maternal Tdap vaccination results in significant interference with infants responses not only to DT but also to conjugated pneumococcal vaccines containing DT mutants as carrier proteins. These interactions after maternal Tdap vaccination need to be taken into account when designing infants' national immunization schedules and choice of vaccines.

FUNDING

The Dutch Ministry of Health, Welfare and Sport.

Correction to: Cost-effectiveness of rule-based immunoprophylaxis against respiratory syncytial virus infections in preterm infants

The name of the co-author Wendy J. Ungar was inadvertently omitted on the original published article. Her name and affiliation have now been added to the author list.

Rectal swabs are a reliable proxy for faecal samples in infant gut microbiota research based on 16S-rRNA sequencing

Rectal swabs are potentially a valuable method for monitoring the gut microbiome in research and clinical settings, where it is important to adhere to strict timing, or where acute sampling is needed. It is currently unknown whether rectal swabs give comparable results to faecal samples regarding microbiota community composition in neonates and infants. To study how well the two sampling methods correlate in infants, we compared the 16S-rRNA-based sequencing results of 131 paired rectal swabs and faecal samples collected from 116 infants at two timepoints in early life. The paired samples were highly comparable regarding both diversity and overall community composition, and strongly correlated on taxonomical level. We observed no significant nor relevant contribution of sampling method to the variation in overall gut microbiota community composition in a multivariable model. Our study provides evidence supporting the use of rectal swabs as a reliable proxy for faecal samples in infant gut microbiota research.

Impact of delivery mode-associated gut microbiota dynamics on health in the first year of life

The early-life microbiome appears to be affected by mode of delivery, but this effect may depend on intrapartum antibiotic exposure. Here, we assess the effect of delivery mode on gut microbiota, independent of intrapartum antibiotics, by postponing routine antibiotic administration to mothers until after cord clamping in 74 vaginally delivered and 46 caesarean section born infants. The microbiota differs between caesarean section born and vaginally delivered infants over the first year of life, showing enrichment of Bifidobacterium spp., and reduction of Enterococcus and Klebsiella spp. in vaginally delivered infants. The microbiota composition at one week of life is associated with the number of respiratory infections over the first year. The taxa driving this association are more abundant in caesarean section born children, providing a possible link between mode of delivery and susceptibility to infectious outcomes.