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IntroductionStreptococcus pneumoniae is a leading cause of pneumonia among children. However, owing to diagnostic limitations, the protection conferred by pneumococcal conjugate vaccines (PCVs) against pediatric pneumonia attributable to vaccine-serotype pneumococci remains unknown.MethodsWe analyzed data on vaccination and nasopharyngeal pneumococcal detection among children

BackgroundReduced-dose pneumococcal conjugate vaccine (PCV) schedules are under consideration in countries where children are recommended to receive 3 doses. Whereas PCV-derived protection against vaccine-serotype colonization is responsible for herd effects of vaccination, dose-specific PCV effectiveness against colonization endpoints is not known. We aimed to assess the performance of differing PCV schedules against vaccine-serotype colonization in children.MethodsFrom 2009-2016, we monitored pneumococcal carriage in southern Israel, where children should receive PCV at ages 2 months, 4 months, and 12 months (2 primary [p] +1 booster [b] schedule). We analyzed nasopharyngeal swabs and vaccination histories from 5928 children aged 0-59 months without symptoms of diseases potentially attributable to pneumococci. Matching individuals on age, sex, ethnicity, visit timing, and recent antibiotic receipt, we measured schedule-specific 7-valent PCV (PCV7) and 13-valent PCV (PCV13) effectiveness against vaccine-serotype colonization in a modified case-control framework. We sampled from the distribution of all possible case-control match assignments for statistical analyses.ResultsReceiving 2 primary-series PCV13 doses conferred 53% (95% confidence interval [CI], 32-67%) protection against PCV13-serotype colonization at ages ≤12 months; 1 primary-series dose was not protective. A 2p+1b PCV13 series conferred 40% (95% CI, 4-67%) and 62% (95% CI, 33-83%) protection against PCV13-serotype colonization at ages 13-24 months and 25-59 months, respectively. Estimates suggested greater PCV13-conferred protection against PCV7-targeted serotypes than the 6 PCV13-only serotypes. As compared to children receiving 2p+1b PCV13 dosing, those receiving 1p+1b and 2p+0b schedules experienced 2.05-fold (95% CI, 1.12-5.00) and 3.33-fold (95% CI, 2.28-4.93) greater odds, respectively, of vaccine-serotype pneumococcal colonization at ages 13-24 months.ConclusionsOur results demonstrate real-world effectiveness of 2p+1b PCV dosing against vaccine-serotype colonization. Reduced-dose schedules may confer lower protection against vaccine-serotype carriage during and beyond the first year of life.

All-cause otitis media (OM) incidence has declined in numerous settings following introduction of pneumococcal conjugate vaccines (PCVs) despite increases in carriage of nonvaccine pneumococcal serotypes escaping immune pressure. To understand the basis for the declining incidence, we assessed the intrinsic capacity of pneumococcal serotypes to cause OM independently and in polymicrobial infections involving nontypeable Haemophilus influenzae (NTHi) using samples obtained from middle ear fluid and nasopharyngeal cultures before PCV7/13 rollout. Data included samples from OM episodes (11,811) submitted for cultures during a 10-year prospective study in southern Israel and nasopharyngeal samples (1,588) from unvaccinated asymptomatic children in the same population. We compared data representing pneumococcal serotype diversity across carriage and disease isolates with and without NTHi coisolation. We also measured associations between the pneumococcal phenotype and the rate of progression from colonization to OM in the presence and absence of NTHi. Whereas pneumococcal serotype diversity was lower in single-species OM than in single-species colonization, levels of serotype diversity did not differ significantly between colonization and OM in mixed-species episodes. Serotypes differed roughly 100-fold in progression rates, and those differences were attenuated in polymicrobial episodes. Vaccine serotype pneumococci had higher rates of progression than nonvaccine serotypes. While serotype invasiveness was a weak predictor of the OM progression rate, efficient capsular metabolic properties-traditionally thought to serve as an advantage in colonization-predicted an enhanced rate of progression to complex OM. The lower capacity of nonvaccine serotypes to cause OM may partially account for reductions in all-cause OM incidence despite serotype replacement in carriage following rollout of PCVs.

BackgroundReductions in otitis media (OM) burden following rollout of pneumococcal conjugate vaccines (PCVs) have exceeded predictions of vaccine impact. In settings with active surveillance, reductions in OM caused by vaccine-targeted pneumococcal serotypes have co-occurred with reductions in OM caused by other pathogens carried in the upper-respiratory tract of children. To understand these changes, we investigated the progression of vaccine-targeted and non-vaccine pneumococcal serotypes from carriage to OM before and after vaccine rollout.MethodsNasopharyngeal carriage prevalence of pneumococcus was monitored in prospective studies of Bedouin and Jewish children

Background Coinfections by Streptococcus pneumoniae and nontypeable Haemophilus influenzae (NTHi) are frequently implicated in complex otitis media. Whereas upper respiratory tract carriage precedes disease for both pathogens, interactions between species in cocolonized hosts are poorly understood. We compared colonization densities and the diversity and fitness of pneumococcal serotypes in single-species and mixed-species colonization.Methods We analyzed nasopharyngeal pneumococcal carriage and nasopharyngeal and oropharyngeal NTHi carriage in 13 541 samples collected over 6909 study visits from 769 children 2-30 months old in a 7-valent pneumococcal conjugate vaccine dosing trial. We measured density associations between the species and compared pneumococcal serotype diversity during and in the absence of NTHi colonization. We used logistic regression to quantify associations between NTHi colonization and previously published pneumococcal serotype factors related to fitness.Results Densities of the 2 species were positively associated when they co-occur in the nasopharynx. NTHi colonization was associated with reduced pneumococcal serotype diversity among children 2-18 months old and was more prevalent among children carrying pneumococcal serotypes with greater capsular thickness, neutrophil resistance, and metabolic efficiency.Conclusions Pneumococcal-NTHi cocolonization is associated with an elevated density of both species and with reduced diversity and increased fitness of pneumococcal serotypes. NTHi colonization may create a selective environment favoring pneumococci with immune-evasive phenotypes.

Streptococcus pneumoniae is a major cause of illness and death worldwide (1,2). It causes otitis media, sinusitis, pneumonia, and invasive pneumococcal diseases (IPD) (1). Capsular polysaccharides are considered the most [...]

BackgroundCocolonization by Streptococcus pneumoniae and Haemophilus influenzae among children has been noted in numerous studies, as has an inverse relationship involving colonization with these species and Staphylococcus aureus. Interactions among these pathogens could mediate unanticipated outcomes of clinical interventions, including changes in H. influenzae and S. aureus disease incidence following pneumococcal vaccine introduction. However, it remains unclear whether cocolonization patterns represent true interspecies interactions or whether they result from confounding factors.MethodsWe investigated polymicrobial carriage using longitudinal data from 369 Bedouin children and 400 Jewish children in Israel who were enrolled in a 7-valent pneumococcal conjugate vaccine (PCV7) trial. Children were swabbed 10 times between 2 and 30 months of age.ResultsThe pathogens followed distinct age and seasonal distributions, but polymicrobial carriage associations persisted after controlling for these and other confounding factors. Receipt of PCV7 resulted in pneumococcal serotype replacement but did not influence total carriage of S. pneumoniae, H. influenzae, or S. aureus.ConclusionsThe fact that S. pneumoniae, H. influenzae, and S. aureus polymicrobial carriage patterns do not result from confounding by age and season supports the idea of active interspecies interactions. However, pneumococcal serotype replacement may prevent changes in H. influenzae and S. aureus carriage among PCV7 recipients.

Utilizing multiplex real time polymerase chain reaction (RT‐PCR) for rapid diagnosis of gastroenteritis, enables simultaneous detection of multiple pathogens. A comparative analysis of disease characteristics was conducted between cases with single and multiple viruses. Rotavirus vaccine was introduced in 2010, reaching a 70% coverage in 2 years. All rectal swabs collected from diarrheic children (<5 years) between December 2017 and March 2022 were included. Detection of the same viruses within 2 months was considered a single episode. Episodes with positive stool bacterial PCR were excluded. A total of 5879 samples were collected, revealing 86.9% (1509) with single virus detection and 13.1% (227) with multiple viruses. The most frequent combination was rotavirus and norovirus (27.8%), these infections followed a winter‐spring seasonality akin to rotavirus. Children with multivirus infections exhibited higher immunodeficiency (OR 2.06) rates, but lower food allergy (OR 0.45) and prematurity rates (OR 0.55) compared to single infections. Greater disease severity, evaluated by the Vesikari score, was observed in multivirus episodes (p < 0.001, OR 1.12). Multivirus infections accounted for 13.1% of symptomatic cases in hospitalized young children. Despite vaccination efforts, rotavirus remained prominent, frequently in co‐infections with norovirus. Overall, multivirus infections were linked to more severe diseases than single virus cases. [ABSTRACT FROM AUTHOR]

Streptococcus pneumoniae is a leading cause of illOness and death worldwide; the highest incidence occurs in children Since the introduction of pneumococcal conjugated vaccine (PCV), a substantial increase in nasopharyngeal [...]