Pneumococcal meningitis in Mexico. Serotype distribution and antimicrobial resistance before and after the introduction of pneumococcal conjugate vaccines in pediatric patients. Results from the GIVEBPVac group.

Long-term surveillance of the effect of PCV13: the future challenge in Africa

Diversity of Serotype Replacement After Pneumococcal Conjugate Vaccine Implementation in Europe

Community-Acquired Pneumonia Incidence in Adults Aged 18 Years and Older in Goto City, Japan: A Prospective Population-Based Study

BackgroundStreptococcus pneumoniae (S. pneumoniae), Haemophilus influenzae (H. influenzae), and Neisseria meningitidis (N. meningitidis) are leading causes of childhood bacterial meningitis and preventable by vaccines. The aim of this hospital-based sentinel surveillance is to describe the epidemiological characteristics of pneumococcal meningitis, including disease burden, and to provide baseline data on pneumococcal serotype distribution to support decision making for pneumococcal conjugate vaccine (PCV) introduction in Vietnam.MethodsSurveillance for probable bacterial meningitis in children 1–59 months of age is conducted in three tertiary level pediatric hospitals: one in Hanoi and two in Ho Chi Minh City. Cerebrospinal fluid (CSF) specimens were collected via lumbar puncture from children with suspected meningitis. Specimens were transferred immediately to the laboratory department of the respective hospital for cytology, biochemistry, and microbiology testing, including culture. PCR testing was conducted on CSF specimens for bacterial detection (S. pneumoniae, H. influenzae, and N. meningitidis) and pneumococcal serotyping.ResultsDuring 2015–2018, a total of 1,803 children with probable bacterial meningitis were detected; 1,780 had CSF specimens available for testing. Of 245 laboratory-confirmed positive cases, the majority were caused by S. pneumoniae (229,93.5%). Of those with S. pneumoniae detected, over 70% were caused by serotypes included in currently available PCV products; serotypes 6 A/6B (27.1%), 14 (19.7%), and 23 F (16.2%) were the most common serotypes. Children with laboratory-confirmed pneumococcal meningitis were more likely to live in Hanoi (p < 0.0001) and children 12–23 months of age were at greater odds (OR = 1.65, 95% CI: 1.11, 2.43; p = 0.006) of having confirmed pneumococcal meningitis compared to children < 12 months of age when compared to those without laboratory-confirmed bacterial meningitis. Additionally, children with confirmed pneumococcal meningitis were more likely to exhibit signs and symptoms consistent with clinical meningitis compared to negative laboratory-confirmed meningitis cases (p < 0.0001) and had a greater odds of death (OR = 6.18, 95% CI: 2.98, 12.86; p < 0.0001).ConclusionsPneumococcal meningitis contributes to a large burden of bacterial meningitis in Vietnamese children. A large proportion are caused by serotypes covered by PCVs currently available. Introduction of PCV into the routine immunization program could reduce the burden of pneumococcal meningitis in Viet Nam.

ABSTRACTStreptococcus pneumoniae is one of the leading causes of meningitis in children. In Japan, since the introduction of the 13-valent pneumococcal conjugate vaccine (PCV13), the number of pneumococcal meningitis due to non-PCV13 serotypes in children has increased. To clarify the clinical outcomes, serotype distributions, and antimicrobial susceptibility of isolated S. pneumoniae strains from pediatric pneumococcal meningitis, we clinically and bacteriologically analyzed 34 cases of pediatric pneumococcal meningitis that were reported after the PCV13 introduction era in Japan. The median age at diagnosis was 1 year (range: 3 months–13 years). Ten (29.4%) patients had underlying diseases. Twenty-nine (85.3%) patients had received at least one dose of any pneumococcal vaccine. Of the 34 patients with pneumococcal meningitis, 6 had sequelae, and 4 died. Nine (26.5%) strains were resistant to penicillin; five (15%) strains to meropenem, with an MIC of 0.5 μg/mL. All strains were susceptible to vancomycin and linezolid. Daptomycin’s MIC50 was 0.064 μg/mL and MIC90 was 0.094 μg/mL. Among the tested strains, only four were PCV13 serotypes. Penicillin-resistant S. pneumoniae was isolated from 30.0% of the patients with sequelae and death. Particularly, the proportion of serotype 10A in the sequelae and deceased cases was significantly higher than that in the complete recovery cases. We should carefully monitor the serotype and drug susceptibility of S. pneumoniae strains isolated from patients with meningitis after the PCV13 era and reconsider the treatment strategy to prepare against further drug-resistant pneumococcal strains.IMPORTANCE We analyzed 34 cases of pediatric pneumococcal meningitis that were reported after the 13-valent pneumococcal conjugate vaccine (PCV13) introduction era in Japan. Our study revealed that pneumococcal meningitis in children was mainly caused by non-PCV13 serotypes; all cases with sequelae and death were caused by non-PCV13 serotypes. Moreover, all serotypes of penicillin resistant Streptococcus pneumoniae strains (26.5%; 9/34) were non-PCV13 serotypes. We also analyzed antimicrobial susceptibilities of glycopeptides, linezolid (LZD), and daptomycin (DAP) of isolated S. pneumoniae strains. All tested strains were susceptible to vancomycin, teicoplanin, LZD, and DAP. Especially. DAP demonstrated the best outcome among the tested antibiotics, with MIC90 of 0.094 μg/mL. Pneumococcal meningitis in children continues to persist and is difficult to control with the current conjugate vaccines. Therefore, it is important to monitor the serotype and antimicrobial susceptibility of S. pneumoniae strains isolated from patients with meningitis and accordingly reconsider the treatment strategy.

Five year burden of Streptococcus pneumoniae infection in under-five children: Observations from Meningitis Surveillance Network, India

Serotype distribution of remaining invasive pneumococcal disease after extensive use of ten-valent and 13-valent pneumococcal conjugate vaccines (the PSERENADE project): a global surveillance analysis

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.

Background Antimicrobial resistance (AMR) is a pressing public health challenge in the Eastern Mediterranean Region (EMR), with Streptococcus pneumoniae being a major contributor due to its role in invasive pneumococcal disease (IPD). Pneumococcal conjugate vaccines (PCVs) have shown promise in reducing vaccine-type IPD and AMR, yet significant barriers persist. Objective This review examines the impact of PCVs on AMR, serotype distribution, and vaccine coverage in pediatric populations within the EMR, emphasizing the interplay between vaccination strategies and AMR trends. Content The introduction of PCVs, particularly PCV13, has led to reductions in vaccine-type IPD and AMR in several EMR countries. For example, post-PCV13 penicillin susceptibility in Saudi Arabia improved from 37 to 100% in invasive isolates, and Lebanon reported significant reductions in vaccine-type AMR. However, challenges such as inconsistent vaccination coverage (e.g., 76% in Yemen, absent in Egypt), socio-political instability, and the emergence of non-vaccine serotypes (NVTs) as per shown in the 73.5% of isolates in Omani children and the high multidrug resistance (MDR) rates (e.g., 85.7% in Yemen) undermine these benefits. Serotype replacement phenomena, driven by ecological shifts, are increasingly contributing to disease burden and AMR. While PCVs reduce the need for antibiotics and limit selective pressures driving resistance, high rates of MDR and inadequate antibiotic stewardship remain concerns. Strengthened vaccination programs, high-valency vaccines, and robust surveillance systems are critical to addressing these challenges. Conclusion PCVs play a pivotal role in mitigating AMR and reducing pneumococcal disease burden in the EMR. However, suboptimal vaccine coverage, NVT emergence, and persistent AMR highlight the need for comprehensive strategies, including enhanced coverage of higher valency vaccines, robust surveillance, targeted public health interventions, strengthened antibiotic stewardship, and improved regional collaboration. Addressing these issues can significantly reduce the AMR burden and improve health outcomes across the region.

Acute lower respiratory infections in Indigenous infants in Australia's Northern Territory across three eras of pneumococcal conjugate vaccine use (2006–15): a population-based cohort study

BackgroundRoutine use of pneumococcal conjugate vaccines (PCVs) in young children has substantially reduced vaccine-type invasive pneumococcal disease (IPD) in the United States and Europe. However, increases in disease and colonization caused by nonvaccine serotypes have been observed, suggesting the need for new PCVs with broader serotype coverage. The aim of this study was to estimate the population-level impact of new PCVs to replace the existing 13-valent vaccine (PCV13) in infants.MethodsAn age-structured dynamic transmission model of Streptococcus pneumoniae before and after PCVs introduction was developed. The model was fit to longitudinal Active Bacterial Core surveillance (ABCs) data (1997–2015) in the United States on distribution and cases of IPD, as well as population level prevalence and serotype distribution data. It was assumed that total S. pneumoniae carriage remains constant over time, with full carriage replacement within four years of introduction of any PCV. Two alternative new PCVs with differing IPD coverage are tested with an introduction date of 2024.ResultsWhen compared with continuing vaccination of infants with PCV13, 10 years after a new PCV is introduced (2,034) cases of IPD are substantially reduced (shown in the table below). Broader serotype coverage leads to greater reductions in IPD. The greatest IPD reduction occurs in the directly vaccinated infant groups, however similar reductions are also observed in the unvaccinated elderly population due to herd protection.Additional Vaccine Coverage Over PCV13 (2016/2024)aIPD Incidence Rate Reduction [%] (2,024 vs. 2,034)<2 Years2–5 Years50–64 Years≥65 YearsAll Ages11–21%/32–35%363533313115–30%/42–45%4242413940 aDefined as the proportion of IPD cases that are caused by serotypes covered by the new PCV in 2016/2024 (a range of values is given because of differences by age group; values differ between 2016 and 2024 as serotype prevalence has not reached steady state as of 2016).ConclusionA new, higher valent PCV given to infants in the United States has the potential to reduce future cases of IPD. Vaccination of infants may also have a substantial indirect benefit on IPD cases in adults and the elderly.Disclosures M. Madin-Warburton, Sanofi Pasteur: Consultant, IQVIA received consultancy fee. A. B. Pitcher, Sanofi Pasteur: Consultant, IQVIA received consultancy fee. M. H. Kyaw, Sanofi Pasteur: Employee, Salary. A. Kieffer, Sanofi Pasteur: Employee, Salary.

Streptococcus pneumonia is still considered a main challenge towards achieving Millennium Development Goal 4 (MDG4) with more than 500000 deaths worldwide among children under 5 years in 2008 (1). Because of the considerable burden of S. pneumonia related diseases such as meningitis, pneumonia, and sepsis, the world health organization (WHO) recommended introduction of pneumococcal conjugate vaccine (PCV) to national routine immunization. Like many countries, Iran is currently preparing to introduce PCV. Epidemiological pattern of S. pneumonia after PCV vaccine implementation will be changed and the prevalence of both nasopharyngeal carriage and transmission will be reduced. In addition, the epidemiology of S. pneumonia is affected among non-targeted vaccination population because of indirect effect of vaccination (1). Prevalence of nasopharyngeal carriage is estimated as 85% in developing countries (2). According to Davis et al. findings, nasopharyngeal carriage following PCV introduction among 14 countries were detected in population groups not targeted for immunization against S. pneumonia (3). Moreover, some studies (4, 5) found that the distribution of vaccine and non-vaccine serotypes has changed after PCV introduction. This epidemiological transition leads to increase in the incidence of those serotypes, which are not included in the PCV vaccine. There are limited or unreliable data on nasopharyngeal carriage and serotype replacement of pneumococcus in Iran. In conclusion, interested researchers in the field of microbiology and epidemiology are advised to conduct repeated surveys or monitor surveillance data to draw the profile of S. pneumonia related diseases at local and national levels.

Conjugate pneumococcal vaccine and antibiotic-resistant Streptococcus pneumoniae: herd immunity and reduction of otitis morbidity.

Indirect impact of PCV10 children vaccination on the serotype distribution and antimicrobial resistance of Streptococcus pneumoniae causing invasive disease in adults over 50 in Colombia, 2005–2019: Observational analysis

Indirect impact of PCV10 children vaccination on the serotype distribution and antimicrobial resistance of Streptococcus pneumoniae causing invasive disease in adults over 50 in Colombia, 2005–2019: Observational analysis