Search Results (99)

Background/Objectives: Pneumonia is a leading cause of hospitalization among children in the United States, with a disproportionate burden in certain racial, socioeconomic, and clinical subgroups. The 13-valent pneumococcal conjugate vaccine (PCV13), introduced in 2010, significantly reduced pneumococcal disease overall, but its effect on disparities in all-cause hospitalized pneumonia (AC-hPNA) remains unclear. This study evaluated changes in AC-hPNA rates by age, race, comorbidity profile, and household income (HHI) before and after PCV13 implementation. Methods: A retrospective cohort study using Optum’s de-identified Clinformatics^® DataMart (2007–2019) included children < 18 years. Rates (per 100,000 person-years) and incidence rate ratios were calculated for four periods: pre-PCV13 (2008–2009), peri-PCV13 (2010–2012), post-PCV13#1 (2013–2016), and post-PCV13#2 (2017–2019). Analyses were stratified by age group and, within each, by race, comorbidity profile (low, at-risk), and HHI. Results: Among 10.1 million children, AC-hPNA rates declined by 51–57% from pre-PCV13 to post-PCV13#2 across all age groups, with the largest reductions in children aged <2 years. Declines occurred across all race, comorbidity, and HHI subgroups; however, rates remained several-fold higher among at-risk children. Persistent disparities were observed among Black children < 2 years, children aged 2–5 years with HHI < $50,000, and children aged 6–17 years with HHI of $50,000–$99,999. Conclusions: Substantial reductions in rates of pediatric AC-hPNA were observed in the period subsequent to the introduction of routine PCV13, yet residual disparities persist among children with comorbidities and select racial and income groups. Targeted strategies are needed to address these gaps. Full article

Background/Objectives: Following the introduction of the 13-valent pneumococcal conjugate vaccine (PCV13) in Oman, this study aimed to characterize the genomic epidemiology, serotype distribution, and antimicrobial resistance (AMR) of Streptococcus pneumoniae causing invasive pneumococcal disease (IPD). Methods: All IPD isolates collected through national laboratory-based surveillance between 2018 and 2021 were analyzed using Whole-Genome Sequencing (WGS). Bioinformatics tools determined serotypes, multilocus sequence types (MLSTs), and Global Pneumococcal Sequence Clusters (GPSCs). Clinical correlates and predictors of mortality were assessed via multivariate logistic regression. Results: A total of 129 IPD isolates were included. Serotype 3 (11.6%) was the most prevalent, followed by 23B and 9N (10.8% each), and 8 (8.5%). PCV13 serotypes accounted for only 26.4% of isolates, while PCV20 coverage reached 59.7%. Significant clonal diversity was observed, with GPSC12 (Serotype 3) and GPSC699 (Serotype 9N/13) being prominent lineages. Multidrug resistance (MDR) was identified in 36.4% of isolates, primarily driven by GPSC6 and GPSC699. The case fatality rate was 23.0%. Advanced age (≥65 years) and clinical presentation with bacteremia were significant independent predictors of death, whereas bacterial genotype and AMR status were not. Conclusions: The findings demonstrate significant serotype replacement in Oman after the introduction of PCV13. The high prevalence of non-vaccine serotypes and emerging MDR clones justifies the transition to higher-valency vaccines like PCV20. Sustained genomic surveillance remains essential to monitor the evolving landscape of invasive pneumococcal lineages. Full article

Background: Pneumococcal conjugate vaccines (PCVs) have substantially reduced pneumococcal disease in children; however, serotype distribution varies geographically, and residual disease due to non-PCV13 serotypes persists. Biological E’s PNEUBEVAX 14^® (BE-PCV14), a WHO-prequalified 14-valent PCV, expands coverage by including serotypes 22F and 33F. As PCVs are co-administered with routine Expanded Programme on Immunization (EPI) vaccines, post-licensure data on safety, co-administration, and lot-to-lot consistency are essential. This multicenter phase IV study evaluated BE-PCV14 in healthy PCV-naïve infants aged 6–8 weeks across 31 sites in India. Methods: A total of 2600 infants were enrolled and vaccinated at 6, 10, and 14 weeks of age; 2300 received BE-PCV14 and 300 received PCV13. All participants received concomitant DTwP-HepB-IPV-Hib and oral rotavirus vaccines per routine schedule. Safety was assessed through solicited and unsolicited adverse events (AEs) and serious adverse events (SAEs). Immunogenicity subsets evaluated responses to co-administered vaccines and serotype-specific responses across three BE-PCV14 lots. Results: Among 2600 vaccinated infants, at least one AE occurred in 26.35% (95% CI: 24.59, 28.19) of BE-PCV14 and 24.67% (95% CI: 20.13, 29.84) of PCV13 recipients; most were mild. Injection-site pain and pyrexia were the most common events. Immune responses to co-administered vaccines were comparable between groups and met the non-inferiority criteria: lower bound of the two-sided 95% CI > −10 percentage points for seroprotection/seroconversion rate differences using the Farrington–Manning method. Lot-to-lot consistency was demonstrated, with all GMC ratios within the predefined equivalence margin (0.5–2.0). Conclusions: BE-PCV14 was well tolerated. Immune responses to co-administered routine EPI vaccines met predefined non-inferiority criteria, supporting the interpretation that BE-PCV14 did not result in clinically meaningful immune interference. Consistent immune responses across manufacturing lots further support its use in infant immunization programs. Full article

Background: Pneumococcal conjugate vaccines (PCVs) prevent severe disease in children, but high costs limit access. PCV10-SII (PNEUMOSIL), a 10-valent PCV prequalified by the World Health Organization (WHO) in 2019, offers a cost-effective alternative. This study assessed its safety and immunogenicity in Vietnamese children aged 6 weeks–24 months. Methods: An open-label, single-arm study enrolled 304 children in three age groups: 6 weeks–6 months (n = 151), >6–12 months (n = 76), and >12–24 months (n = 77). Participants received two or three doses. Safety was evaluated through immediate reactions, adverse events (AEs), serious adverse events (SAEs), and withdrawals. Immunogenicity was measured 28 days after the final dose using serotype-specific IgG geometric mean concentrations (GMCs), opsonophagocytic activity (OPA) titers, and seroresponse rates. The trial was approved by the IRB of the National Ethics Council (code: No. 75/CN-HĐĐĐ on date 4 June 2021) and was registered with ClinicalTrials.gov, NCT05140720. Results: Of 304 enrolled participants, 294 (96.7%) completed follow-up. No immediate adverse events or serious adverse events occurred. Unsolicited adverse events were reported in 17%, mainly respiratory, while serious adverse events occurred in 4%. Mild local/systemic reactions (e.g., injection site pain, crying) resolved without sequelae. Immunogenicity was strong, with GMCs 1.8–9.11 µg/mL, GMTs 277.8–22,342, and seroresponse rates >90% for 9 of 10 serotypes, serotype 6B demonstrated a slightly lower seroresponse rate of 88.6%. Conclusions: PCV10-SII demonstrated favorable safety and robust immunogenicity, supporting its inclusion in national immunization programs as an affordable option for pneumococcal disease prevention. Full article

Background: Vietnam is one of few remaining countries without a pediatric pneumococcal National Immunization Program (NIP). However, four pneumococcal conjugate vaccines (PCVs) are available in Vietnam: 10-, 13-, 15-, and 20-valent PCVs (PCV10, PCV13, PCV15 and PCV20). Given the availability of multiple PCVs, selecting an optimal vaccination strategy is challenging. This paper aims to estimate the vaccination impact of these PCVs, with and without the implementation of a pediatric NIP, to inform decision-makers and healthcare providers. Methods: A Markov model was adapted to evaluate the impact of all vaccines administered under a 3 + 1 schedule (50% vaccine uptake with direct protection assumed only) and a hypothetical scenario including PCVs 2 + 1 in Vietnam’s pediatric NIP (90% uptake with both direct and indirect protection) from a payer’s perspective. For each scenario, we performed stepwise comparisons of each vaccine with the next higher-valent option: PCV13 versus PCV10, PCV15 versus PCV13, and PCV20 versus PCV15. Results: Under the 3 + 1 schedule, PCV13 and PCV20 were cost-effective versus PCV10 and PCV15, respectively. PCV15, however, was not cost-effective versus PCV13, though offering greater health benefit but at a higher total cost. Under the 2 + 1 schedule, PCV13 remained cost-effective over PCV10, while PCV15 was not cost-effective relative to PCV13. PCV20 was dominant over PCV15. Sensitivity analyses demonstrated results consistent with both reference cases. Conclusions: Vaccinating infants in Vietnam through the private market or an NIP with PCV13 or PCV20 was estimated to be more cost-effective or cost saving than strategies based on PCV10 or PCV15, respectively. These findings provide valuable evidence to inform policy decisions. Full article

Background/Objectives: Infant pneumococcal conjugate vaccines (PCV) have significantly reduced pneumococcal morbidity and mortality. Newer vaccines, 15-valent (PCV15) and 20-valent (PCV20), offer broader serotype coverage, potentially preventing more disease. This study estimated the number needed to vaccinate (NNV) to prevent one disease outcome for infant PCV20 and PCV15 programs versus 13-valent PCV (PCV13). Countries from Europe, the Asia-Pacific, and the Americas were included. Methods: A multi-cohort, population-based model estimated the cumulative NNVs for infant programs with PCV20 and PCV15 relative to PCV13 in 21 countries. Outcomes included overall pneumococcal case, hospitalization, and death. The ratio of PCV15 NNVs to PCV20 NNVs was calculated. Probabilistic sensitivity analysis (PSA) and scenario assessments tested results’ robustness. Results: Across 21 countries, the median of country-specific NNV estimates to prevent one pneumococcal case was 13 with PCV20 and 80 with PCV15. Median NNVs to prevent a hospitalization or death were 44 and 568 with PCV20 and 203 and 2203 with PCV15, respectively. PCV20 demonstrated lower NNVs than PCV15 across all countries and outcomes. Median NNV ratios for PCV15 versus PCV20 were 5.1 (case), 4.5 (hospitalization), and 4.2 (death). No clear geographic differences were observed. PSA and scenario analyses indicated stable results with minimal deviations. Conclusions: Infant immunization with PCV20 is associated with lower NNVs than PCV15. To achieve the same disease reduction as PCV20, over five times as many children would need to be vaccinated with PCV15. These findings suggest PCV20 may offer greater public health impact compared with PCV15 in infant immunization programs. Full article

Background: Streptococcus pneumoniae is a leading cause of child mortality in Nepal despite the introduction of the 10-valent pneumococcal conjugate vaccine (PCV10). Vaccine effectiveness is threatened by the emergence of non-vaccine serotypes (NVTs) and the multiple serotypes carriage which often fail to be detected by traditional methods. We aimed to study changes in serotype distribution before and after PCV10 immunization among infants, including serotype dominance in Nepalese infants in the post-vaccine era. Methods: We enrolled infants in a longitudinal cohort study (2020–2022) conducted in Bhaktapur, Nepal. Nasopharyngeal swabs were collected before PCV10 dose 1 (6 weeks) and at 9 and 12 months post-immunization. We used a sensitive nanofluidic qPCR platform to detect multiple serotypes and establish their hierarchy by quantifying the bacterial load of each strain. Inverse Probability Weighting (IPW) adjusted risk factor analysis was used to account for loss to follow-up. Results: PCV10 successfully reduced vaccine-type (VT) carriage, declining sharply from 32.8% at 6 weeks to 4.8% at 12 months. VTs were pushed from being the dominant strain to occupying subdominant roles in co-colonization. Conversely, NVTs rapidly filled the vacated niche, showing a significant increase in their dominant status (p < 0.001). The most common replacing NVTs that rose to dominance were 35B, 19A, 6C/6D, and 15B/15C. Significant risk factors for carriage included older infancy (aOR 3.4, 95%CI: 2.6–4.5 at 9 months), a household kitchen in the living area (aOR 1.4, 95%CI: 1.0–1.9), and winter (aOR 1.7, 95%CI: 1.5–2.7) and pre-monsoon seasons (aOR 2.0, 95%CI: 1.5–2.8). Conclusions: While PCV10 reduced overall VT circulation, the persistence of VTs in subdominant niches creates a continuous reservoir for potential re-emergence and antibiotic resistance. This clear hierarchical shift in dominance towards NVTs underscores the urgent need for a public health strategy that includes the adoption of a higher-valent PCV to provide broader protection, and interventions targeting environmental risk factors are essential to sustain long-term reductions in pneumococcal colonization. Full article

Background/Objectives: Streptococcus pneumoniae (S. pneumoniae) remains a leading cause of invasive bacterial disease in children worldwide. In Tunisia, the 10-valent pneumococcal conjugate vaccine (PCV10) was introduced into the national immunization program in 2019 for children under two years of age. This study aimed to assess molecular epidemiology, antimicrobial resistance, and vaccine impact on pediatric invasive pneumococcal disease (IPD) before and after PCV10 introduction. Methods: A retrospective study was conducted at Bechir Hamza Children’s Hospital (Tunis, Tunisia) between 2016 and 2022. IPD isolates were characterized by multiplex PCR, antimicrobial susceptibility testing, and whole-genome sequencing. Serotyping was performed using three approaches: multiplex PCR, SeroBA, and a novel cpsB gene-based algorithm. Genomic diversity and population structure were analyzed through molecular typing approaches. Incidence trends were calculated using national population data. Results: Among 150 confirmed IPD isolates, vaccine-type (VT-PCV10) strains decreased significantly from 69.8% before to 47.2% after vaccine introduction (p = 0.013), with serotype 14 showing the largest decline. Genomic analysis identified 43 sequence types and 27 global pneumococcal sequence clusters, reflecting high genetic heterogeneity. The cpsB approach demonstrated strong concordance with PCR (κ = 0.67) and SeroBA (κ = 0.85). The mean annual incidence of VT disease in children aged 0–4 years declined from 1.28 to 0.86 cases per 100,000 population, while non-vaccine serotypes showed a modest increase. Conclusions: PCV10 introduction was associated with a marked reduction in vaccine-type IPD among young children, supporting its public health benefit. Ongoing genomic surveillance remains essential to monitor serotype replacement and antimicrobial resistance in Tunisia. Full article

Background/Objectives: American Indian/Alaska Native individuals exhibit a higher prevalence of carriage of Streptococcus pneumoniae and are at increased risk of invasive pneumococcal disease compared with the general US population, driven by persistent inequities in health determinants. Although the use of pneumococcal vaccines has reduced carriage of vaccine serotypes, the prevalence of carriage of non-vaccine serotypes has increased. Methods: This study was a descriptive subgroup analysis of the PNEU-DAY study (NCT03547167; EudraCT 2017-004915-38). Safety, tolerability, and immunogenicity of sequential administration of either V114, a 15-valent pneumococcal conjugate vaccine (PCV), or 13-valent PCV (PCV13), followed 6 months later by 23-valent pneumococcal polysaccharide vaccine (PPSV23), were evaluated in pneumococcal vaccine-naïve American Indian adults with or without pre-defined risk factors for pneumococcal disease. Polymerase chain reaction testing assessed nasopharyngeal/oropharyngeal carriage of S. pneumoniae. Results: Following administration of PCV and PPSV23, the proportions of participants with adverse events were generally comparable between vaccination groups. V114 and PCV13 were immunogenic for all respective vaccine serotypes, with V114 inducing robust immune responses to the two additional serotypes not included in PCV13 (22F and 33F), based on opsonophagocytic activity geometric mean titers and immunoglobulin G geometric mean concentrations at 30 days post-vaccination. Sequential administration with PPSV23 was immunogenic in both vaccination groups. Nasopharyngeal/oropharyngeal carriage of S. pneumoniae was observed in 16.7% to 22.6% of American Indian participants across the study timepoints. Conclusions: V114 was well tolerated and immunogenic for the 15 serotypes in V114 when administered either alone or followed by PPSV23. Use of V114 has the potential to expand serotype coverage and protect against pneumococcal disease resulting from serotypes absent in PCV13 among American Indian adults. Full article

Background: Mozambique introduced the 10-valent pneumococcal conjugate vaccine (PCV10) in 2013 using a three-dose primary series with no booster dose (3p+0) and later switched to the PCV13 using a schedule of two primary doses with one booster (2p+1). We aimed to describe the burden and serotype distribution of pneumococcal meningitis in children under 5 years of age in Mozambique over an eleven-year period starting with the year of PCV10 introduction, and assess the impact of the PCV vaccine and schedule changes. Methods: We analysed meningitis surveillance data in Mozambique from March 2013 through to December 2023. Cerebrospinal fluid (CSF) samples were collected from eligible children in three referral hospitals (Maputo Central Hospital [south], Beira Central Hospital [central], and Nampula Central Hospital [north]). Culture and polymerase chain reaction assay (qPCR) were performed on each sample. S. pneumoniae-positive samples were subsequently serotyped using multiplex assay. We estimated annual incidence rates for pneumococcal meningitis in children under 5 years old following the PCVs’ introduction (2013–2023). The impact of the product switch and schedule change from PCV10/3p+0 to PCV13/2p+1 on the burden and serotype distribution of pneumococcal meningitis was assessed. Results: Of the 4075 CSF samples tested, 7.4% (301/4075) were positive for S. pneumoniae, 2.5% (103/4075) for H. influenzae, and 1.0% (42/4075) for N. meningitidis. Pneumococcal meningitis incidence in children under five reduced from 44.7 cases per 100,000 in 2013 to 4.6 cases per 100,000 in 2023, an 89.7% reduction. In the PCV13/2p+1 period (2020–2023), pneumococcal meningitis incidence was 51.2% lower than the PCV10/3p+0 period (2013–2017) (IRR 0.49, 95% CI 0.4–0.6; p < 0.001). PCV10-serotype pneumococcal meningitis incidence among children under five decreased by 65.6% in the PCV13/2p+1 period (IRR 0.34, 95% CI 0.2–0.6; p < 0.001). We detected zero cases of pneumococcal meningitis due to the PCV13-serotype in 2020–2023, whereas non-PCV10/13-serotypes increased by 76% (IRR 1.76, 95% CI 1.2–2.6; p = 0.004). The case–fatality proportion decreased by 71.9% (95% CI 62.9–84.8%) in the PCV13/2p+1 period. Conclusions: Since the introduction of PCVs in Mozambique, the burden of pneumococcal meningitis and deaths in children under 5 years of age has substantially decreased, as well as the prevalence of PCV13-serotypes. Higher valency PCVs are needed due to the increased prevalence of non-PCV10/13-serotypes. Funding: Gavi, The Vaccine Alliance, reference number: MOZ-HSS-2-INS; WHO Reference: 2014405143-0, creation DFC to support HIB & Surveillance System. Full article

Objectives: This study systematically assessed the safety and immunogenicity of a new 13-valent pneumococcal conjugate vaccine (CRM197/TT, PCV13i) against the licensed PCV13 vaccine in a cohort of Chinese children between 12 and 23 months of age. Methods: This is a phase III, randomized, double-blind trial (NCT04841369). A total of 528 participants were randomized 1:1 to receive two doses of either PCV13i experimental or the PCV13 control vaccine at a 2-month interval, with 517 participants completing the vaccinations. Results: The overall incidence of adverse events (37.12% vs. 32.70%, p = 0.134) and adverse reactions (24.81% vs. 21.61%, p = 0.221) was comparable between the experimental and control groups. Local adverse reactions were more frequent in the experimental group (10.00% vs. 6.12%, p = 0.021), such as erythema (7.88% vs. 4.02%, p = 0.008). Systemic adverse reactions, including fever (10.77% vs. 13.77%), showed no significant differences. No vaccine-related serious adverse events occurred. Immunogenicity assessments showed that seropositivity rates for most serotypes reached ≥96% in both groups, with eight serotypes achieving 100% seropositivity in the experimental group. PCV13i induced higher IgG geometric mean concentrations (GMCs) for serotypes 3, 7F, and 19F (p < 0.05), whereas the control group showed higher GMCs for serotypes 1, 5, 6A, and 14 (p < 0.05). Opsonophagocytic activity (OPA)-related geometric mean titers (GMTs) were superior for PCV13i against serotypes 7F (39,583 vs. 17,249, p < 0.001) and 19F (1517 vs. 983, p = 0.028), but lower for serotype 5 (13 vs. 93, p < 0.001). Conclusions: PCV13i demonstrated non-inferior immunogenicity and an acceptable safety profile in 12–23-month-old children. Full article

Background/Objectives: The 20-valent pneumococcal conjugate vaccine (PCV20) was approved for use in children and infants on the basis of studies comparing its safety and immunogenicity with those of the 13-valent vaccine (PCV13). PCV20 offers expanded coverage of seven additional serotypes. This meta-analysis aimed to summarize the available evidence on the comparative immunogenicity between PCV20 and PCV13. Methods: A systematic search of the PubMed, Web of Science, Scopus, Cochrane, and ClinicalTrials.gov databases was conducted in September 2024. The following inclusion criteria were used: (i) design: randomized clinical trials; (ii) outcomes: studies that included immunogenicity outcomes; (iii) compared vaccines: any study directly comparing the immunogenicity of PCV20 and PCV13; and (iv) population: infant population <2 years of age. No language or temporal restrictions were applied in the study. A random-effects meta-analysis was conducted via the Hartung–Knapp–Sidik–Jonkman method, with subgroup analyses according to the serotype and vaccination schedule (3 + 1 and 2 + 1). We used the revised Cochrane risk of bias 2 tool (RoB 2.0) to assess the risk of bias. The following parameters of immunogenicity were estimated: (i) the pooled geometric mean ratio (GMR PCV20/PCV13) of serotype-specific pneumococcal anticapsular antibodies, (ii) the pooled difference (PCV20-PCV13) in the percentage (DP) of participants who achieved predefined antibody levels for each serotype, and (iii) the pooled geometric mean titres (GMTs) of serotype-specific opsonophagocytic activity (OPA) in PCV20 and PCV13, along with their 95% confidence intervals (95% CIs). Results: Four studies (4093 infants aged 42–180 days) that compared the PCV20 and PCV13 vaccines, published between 2021 and 2024, were included in this meta-analysis. The immunogenicity of both groups was compared one month after the primary series and one month after the booster dose. The pooled results indicated that PCV20 elicited lower immune responses for the 13 serotypes shared with PCV13, according to the GMR and OPA outcomes. For the DP outcome, no statistically significant differences were observed between the two groups. Immune responses were higher for the additional serotypes in the PCV20 group; however, these differences were not statistically significant for all serotypes. Conclusions: This meta-analysis offers an overview of the evidence on the comparative immunogenicity of PCV20 and PCV13. Although some outcomes indicate that PCV20 elicits lower immune responses for the 13 serotypes shared with PCV13, it provides immunity against seven additional serotypes associated with IPD. Further studies are warranted to strengthen the evidence base, and continuous IPD surveillance remains essential to monitor shifts in serotype prevalence, assess the impact of current and future vaccines, and guide vaccine policy recommendations. Full article

Background: COPD and stable angina are common in older adults, increasing the risk of respiratory and cardiovascular complications. Pneumococcal vaccination is recommended to reduce this burden. This study evaluated the 10-year impact of 13-valent pneumococcal conjugate vaccine (PCV13) on community-acquired pneumonia (COPD), COPD exacerbations, hospitalizations, and survival in this cohort. Methods: A total of 483 male patients with COPD and/or stable angina received a single dose of PCV13 and were divided into three groups: Group 1 (n = 140): vaccinated with COPD; Group 2 (n = 167): vaccinated with COPD and stable angina; and Group 3 (n = 176): unvaccinated with COPD. Primary endpoints were CAP cases, COPD exacerbations, and hospitalizations; the secondary endpoint was survival. Analysis used generalized linear models, Cox regression, and Kaplan–Meier survival curves. Results: PCV13 significantly reduced CAP in patients with COPD alone but not in those with comorbid angina. Although CAP, exacerbations, and hospitalizations increased over time, vaccinated groups consistently showed lower rates than the unvaccinated group. Survival was higher in both vaccinated groups over 10 years. Conclusions: PCV13 was associated with a reduced risk of CAP, COPD exacerbations, hospitalizations, and improved survival in older adults with COPD and stable angina. These findings support the vaccine’s potential to improve outcomes in multimorbid populations and its inclusion in clinical guidelines and adult immunization programs for high-risk older adults. Full article

Background: Trust in information sources is essential to enhance an individual’s understanding of the message and boost their willingness to change or act on specific health behavior, including vaccine uptake. This study explores the association between trust in information sources and parents’ knowledge, attitudes, and practices regarding their children’s 13-valent pneumococcal conjugate vaccine (PCV13) uptake across seven cities in the Yangtze River Delta (YRD) region in China. Methods: A cross-sectional web-based survey was conducted from May to June 2023. Adult parents (N = 1304) who had at least one child aged 24 months or less and lived in the YRD region were recruited. The Adjusted Ordinary Least Squares (OLSs) regression model was applied to estimate the association between participants’ level of trust in different information sources and their knowledge, attitudes, and practices of children’s PCV13 vaccination. Results: Information from the Disease Control and Prevention Center (CDC) source received the highest trust score. Age, gender, education, and annual household income were related to varied trust levels in specific sources. Trust in the health service provider source was significantly associated with a better command of PCV13 knowledge, acceptance of PCV13, and a higher likelihood of vaccination. Trust in online community sources was positively associated with vaccine uptake. Conclusions: The study participants highly trusted information from health service provider sources. These sources may be effective channels with potential to enhance parents’ vaccine knowledge and acceptance of PCV13. Public health workers could utilize trusted sources to disseminate the benefits of the PCV13 and encourage the uptake of the vaccine. Full article

Background/Objectives: The immunogenicity of Streptococcus pneumoniae vaccines is commonly evaluated by assessing the fold increase or proportions exceeding 0.35 μg/mL in serotype-specific IgG antibody levels post-vaccination. Establishing baseline antibody levels in unvaccinated populations is therefore essential for defining serological thresholds and understanding naturally acquired immunity. This study aimed to assess the seroprevalence and baseline levels of IgG antibodies specific to 13 pneumococcal capsular polysaccharide serotypes in healthy infants and young children across multiple regions of China from 2016 to 2023, supporting evidence-based PCV13 vaccination strategies. Methods: IgG concentrations for 13 serotypes (1, 3, 4, 5, 6A, 6B, 7F, 9V, 14, 18C, 19A, 19F, and 23F) were measured in unvaccinated individuals using the WHO-recommended ELISA. Univariate and multivariate analyses were applied to evaluate regional, age, and gender effects on baseline antibody levels. Results: GMCs for serotypes 6B, 14, 19A, and 19F exceeded 0.35 μg/mL, with 14 being the highest (1.64 μg/mL) and serotypes 3 and 4 the lowest. Significant regional variation (p < 0.001) and a U-shaped age trend were observed, with the lowest being at 7–11 months (p = 0.003). Conclusions: Baseline IgG levels varied by region and age. No significant gender differences were observed, and overall antibody levels were higher in the southern region. Full article