Topline Findings
- Robust Pediatric Immune Response: Capvaxive was found to elicit strong immune responses in children and adolescents aged 2 to <18 years at increased risk of pneumococcal disease, covering all 21 vaccine serotypes.
- Broader Protection Against Invasive Pneumococcal Disease (IPD): The vaccine provides potential coverage for up to 78% of IPD cases in high-risk pediatric populations, including 11 serotypes not found in other pediatric vaccines.
- Global Regulatory Approval and Safety: Capvaxive is approved in the US, EU, Japan, and multiple countries worldwide, supported by safety and immunogenicity data from the Phase III STRIDE clinical program.
Results from the Phase III STRIDE-13 trial (NCT06177912) showed that Merck’s Capvaxive (Pneumococcal 21-valent Conjugate Vaccine) demonstrated robust immune responses in children and adolescents aged 2 to <18 years who are at increased risk of pneumococcal disease due to chronic medical conditions.
According to the company, these findings highlight Capvaxive’s potential to provide broader protection against pneumococcal disease in vulnerable pediatric populations, complementing existing vaccination strategies and addressing unmet needs for additional coverage against serotypes not included in other approved vaccines.1
Could Capvaxive Provide Broader Pneumococcal Protection for Vulnerable Pediatric Populations?
“Children and adolescents living with chronic medical conditions are at increased risk of pneumococcal disease and offering them additional protection is essential,” said STRIDE-13 trial, investigator Rotem Lapidot, chief of pediatric infectious diseases, Rambam Health Care Campus, in a press release. “Results from STRIDE-13 demonstrate the potential of Capvaxive to deliver protection for these vulnerable populations, who may benefit from additional pneumococcal disease coverage by including serotypes not contained in other approved pneumococcal infant regimens.”
STRIDE-13 Trial Design and Findings
- The randomized, double-blind, active comparator-controlled STRIDE-13 trial evaluated the immunogenicity, safety, and tolerability of Capvaxive compared to PPSV23 in 882 children and adolescents aged ≥2 to <18 years with increased risk for pneumococcal disease due to medical conditions.
- Patients were randomly assigned in a 3:2 ratio to receive a single dose of Capvaxive or PPSV23, following completion of a primary pediatric pneumococcal vaccine regimen.
- Primary endpoints of the trial included the percentage of patients with solicited injection-site adverse events (AEs), percentage of patients with solicited systemic AEs, and percentage of patients with vaccine-related serious AEs.1,2
- Results showed that Capvaxive generated immune responses against all 21 serotypes, was comparable to PPSV23 for the 12 shared serotypes, and showed superior responses for the nine serotypes unique to Capvaxive.
- Safety and tolerability were similar between the two vaccines, with AEs generally mild and consistent with expectations.1
- According to the Centers for Disease Control and Prevention, pneumococcal disease results in approximately 300,000 deaths in children under five years of age annually.
- Most of these cases have been reported in developing countries. However, vaccines that have been introduced in developing countries have helped support declining rates.3
CapvaxiveCoverage and Regulatory Status for Invasive Pneumococcal Disease
Capvaxive was originally developed for adults and provides coverage against the pneumococcal serotypes responsible for roughly 84% of invasive pneumococcal disease (IPD) cases in adults aged 50 years and older, compared with about 52% coverage offered by PCV20, according to CDC data from 2018 to 2022.
Merck stated that the vaccine could offer broader protection in children and adolescents at increased risk, covering around 78% of IPD cases. This includes 11 serotypes not found in other pediatric vaccines, which account for approximately 34% of cases in this age group based on CDC data from 2019 to 2023.
Capvaxive has received regulatory approval in the United States, European Union, Japan, and several other countries globally, supported by safety and immune response data from the STRIDE clinical program.1
“While Capvaxive was designed to specifically cover the serotypes that cause the majority of (IPD) cases in adults, findings from STRIDE-13 underscore its added potential to help protect children and adolescents who are at an increased risk,” said Paula Annunziato, SVP, infectious diseases and vaccines, global clinical development, Merck Research Laboratories, in the press release. “We are encouraged by the safety and immunogenicity data presented at the 6th ESCMID Conference on Vaccines, which underpin our commitment to ensuring infants and adults have access to protection against invasive pneumococcal disease.”
References
- CAPVAXIVE® (Pneumococcal 21-valent Conjugate Vaccine) Demonstrates Positive Immune Responses in Children and Adolescents at Increased Risk of Pneumococcal Disease. Merck. September 11, 2025. Accessed September 12, 2025. https://www.merck.com/news/capvaxive-pneumococcal-21-valent-conjugate-vaccine-demonstrates-positive-immune-responses-in-children-and-adolescents-at-increased-risk-of-pneumococcal-disease/
- A Clinical Study of the V116 Vaccine for Children and Teenagers (V116-013) (STRIDE-13). Clinicaltrials.gov. Accessed September 12, 2025. https://clinicaltrials.gov/study/NCT06177912?intr=v116&rank=1
- Pneumococcal Disease Surveillance and Trends. CDC. Accessed September 11, 2025. https://www.cdc.gov/pneumococcal/php/surveillance/index.html
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