PCVs Significantly Reduce Pneumococcal Meningitis in Children

Following the introduction of pneumococcal conjugate vaccines (PCVs) in Mexico, children’s burden of pneumococcal meningitis decreased significantly, according to a study published in the Journal of Infection and Public Health.¹

However, with the continued prominence of nonvaccine and commonly appearing pneumococcal serotypes, higher-valent PCVs are necessary to manage pneumococcal surveillance and evaluation in the future.

“Immunization with PCVs has been particularly effective in reducing the burden of pneumococcal meningitis,” wrote the authors of the study.¹ “However, the emergence and expansion of non-vaccine Streptococcus pneumoniae (S. pneumoniae) serotypes have been documented in several countries, indicating that pneumococcal meningitis remains a persistent public health challenge.”

READ MORE: IPD Serotypes Decreased Significantly During the COVID-19 Pandemic

For meningitis and most all pneumococcal diseases, the PCV has been a revolutionary innovation throughout the 21st century. Prior to the year 2000, pneumococcal polysaccharide vaccines were the standard of care for protecting against said diseases. However, the 7-valent PCV (PCV7) was introduced in 2000,² and the PCV market has continued to boom, now offering PCV13, PCV15, PCV20, and PCV21, with more currently in development.³

Despite the novelty of pneumococcal vaccines regularly coming to market, pneumococcal meningitis remains an issue in geographical locations that have experienced spikes in nonvaccine serotype carriage.

For example, a recent article published this summer in Vaccine found similar trends across the nasopharyngeal carriage of S. pneumoniae vaccine serotypes. While they observed an overall decrease in serotypes covered by vaccines, there were significant increases in nonvaccine serotypes 3, 6A, 14, and 19A even after the rollout of PCVs.⁴

On top of shifting serotype distribution nonreliant on PCV development, there are also concerns of antimicrobial resistance (AMR) and a need for deeper investigations.

“Despite vaccine implementation, S. pneumoniae has demonstrated resistance to multiple classes of antibiotics, including penicillin, third-generation cephalosporins, macrolides, fluoroquinolones, and trimethoprim-sulfamethoxazole,” they continued.¹ “The aim of this study is to analyze the serotype distribution and AMR patterns of S. pneumoniae isolates causing meningitis in children, before and after the introduction of PCVs into the national immunization program (NIP).”

To better understand the distribution of bacteria causing pediatric meningitis, researchers conducted a prospective analysis of pneumococcal isolates spanning data from 1993 to 2024. Isolates were collected through the GIVEBPVac surveillance network and included data from children under 18 years old diagnosed with meningitis throughout the 30-year study period.

Furthermore, comparing serotype distribution with vaccine impact, the researchers also separated data into 3 distinct timeframes related to PCV development. The prePCV period was considered 1999 to 2007, when no PCV was introduced into Mexico’s NIP despite limited use of PCV7 in private practice. The PCV7/PCV10 period lasted from 2008 to 2011, when those 2 vaccines were in national use. Finally, the PCV13 period was 2012 to 2024.

With PCV13 being the most recent pneumococcal vaccine in Mexico’s NIP, vaccine serotypes were defined as those either within or not within (nonvaccine serotypes) PCV13.

The final analysis included 575 pneumococcal isolates from children with meningitis over the 30-year period.

“The proportion of PCV13 serotypes declined from 77.2% in the pre-PCV period to 33.3% in the PCV13 period, while non-vaccine serotypes rose to 66.7%. Serotypes 14, 6B, 19F, and 23F were predominant before PCV introduction,” the authors wrote.¹ “In the PCV13 era, serotypes 19A and 15B increased in frequency, while 23B and 6C emerged among non-vaccine serotypes.”

Similar to the aforementioned study published in Vaccine, researchers uncovered a decline in PCV13 serotypes and an increase in nonvaccine serotypes persisting throughout the study period. AMR also increased significantly for cefotaxime specifically, rising from 22.8% of the population to 30.4% during the PCV13 period.

While working to increase awareness and uptake of PCVs is crucial in sustaining minimal cases of pneumococcal meningitis, serotype surveillance has increasingly been paramount to the overall disease burden. As the general health care community’s understanding of S. pneumoniae serotypes increases, it continues to be the first step in developing greater population-wide protection from pneumococcal diseases.

“PCVs significantly reduced the burden of pneumococcal meningitis in Mexican children,” they concluded.¹ “However, the emergence of non-vaccine serotypes and the persistence of serotype 19A highlights the need for continued surveillance and evaluation of higher-valent vaccines to inform future immunization strategies.”

READ MORE: Pneumococcal Resource Center

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REFERENCES

1. Carnalla-Barajas MN, Soto-Noguerón A, Solórzano-Santos F, et al. 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. J Infect Public Health. 2025;19(1):103030. https://doi.org/10.1016/j.jiph.2025.103030

2. Gierke R, Wodi AP, Kobayashi M. Chapter 17: pneumococcal disease. CDC. May 1, 2024. Accessed November 24, 2025. https://www.cdc.gov/pinkbook/hcp/table-of-contents/chapter-17-pneumococcal-disease.html

3. Pneumococcal vaccination. CDC. October 26, 2024. Accessed November 24, 2025. https://www.cdc.gov/pneumococcal/vaccines/index.html

4. Ngocho JS, van der Gaast-de Jongh CE, Sebba J, et al. Emergence of non-vaccine Streptococcus pneumoniae serotypes colonizing the nasopharynx of children under five years of age in the 13-valent pneumococcal conjugate vaccine era in Tanzania. a short communication. Vaccine. 2025;61:127336. https://doi.org/10.1016/j.vaccine.2025.127336