FDA clears Capvaxive as supplemental PCV for at-risk children

The FDA has approved an expanded indication for Capvaxive (pneumococcal 21-valent conjugate vaccine; Merck) to include children and adolescents aged 2 through 17 years who have completed a primary pediatric pneumococcal vaccination series and have one or more chronic medical conditions that increase their risk for pneumococcal disease.¹

The decision, announced in June 2026, makes Capvaxive the first and only pneumococcal conjugate vaccine (PCV) specifically indicated and studied in the United States for use as a supplemental dose in this high-risk pediatric population, according to Merck.¹

"Children and adolescents with certain chronic conditions are at an increased risk for pneumococcal disease, including pneumonia, meningitis, and bloodstream infections," said Rotem Lapidot, MD, chief of pediatric infectious diseases at Rambam Health Care Campus and an investigator in the STRIDE-13 trial. "This approval recognizes the potential of Capvaxive to deliver additional protection by including serotypes not contained in approved primary pediatric PCV series, and represents a new approach to helping protect children and adolescents at increased risk for pneumococcal disease."¹

STRIDE-13 trial design and results

The approval is based on data from the phase 3 STRIDE-13 trial (NCT06177912), a randomized, double-blind, active comparator-controlled study that evaluated Capvaxive against PPSV23 (pneumococcal 23-valent polysaccharide vaccine) in 874 children and adolescents aged 2 through 17 years.^1,2 Eligible participants had at least one prespecified chronic condition—diabetes mellitus, chronic heart disease, chronic kidney disease, chronic liver disease, or chronic lung disease—and had previously completed a primary pneumococcal vaccination series (PCV7, PCV10, or PCV13) at least 8 weeks before enrollment. Participants were randomly assigned 3:2 to receive a single dose of Capvaxive (n = 527) or PPSV23 (n = 347).

The primary immunogenicity end point was serotype-specific opsonophagocytic activity (OPA) geometric mean titer (GMT) at 30 days post-vaccination. Capvaxive was noninferior to PPSV23 for the 12 serotypes shared between the 2 vaccines and induced statistically significantly greater OPA GMTs compared with PPSV23 for each of the 9 serotypes unique to Capvaxive. The vaccine also elicited immune responses to serotype 15B, which is cross-reactive with serotype 15C.^1,2 Rates of adverse events, including systemic and serious vaccine-related adverse events, were generally comparable between the 2 groups.

Epidemiologic modeling based on 2015–2019 CDC Active Bacterial Core surveillance data estimated that Capvaxive covers serotypes responsible for approximately 79% of invasive pneumococcal disease (IPD) cases in at-risk children younger than 18 years; the 11 serotypes unique to Capvaxive —not covered by primary pediatric PCV series—account for an estimated 40% of IPD cases in this risk group.¹ These estimates are derived from surveillance data and do not reflect vaccine efficacy.

Clinical context and unmet need

Despite the substantial reductions in vaccine-serotype IPD achieved since the introduction of PCV7 in 2000, children with underlying chronic conditions continue to carry a disproportionate burden of pneumococcal disease.³ Published data indicate that roughly half of IPD cases among children have an associated comorbidity, with the most common including asthma, prematurity, and neuromuscular disorders.³

The current US primary pediatric pneumococcal vaccination schedule uses PCV15 or PCV20, both of which cover different—but overlapping—serotype profiles compared with Capvaxive. The new supplemental indication is intended to extend coverage, particularly against non-vaccine serotypes that have risen in relative prominence following widespread PCV13 use.

Vaccine background

CAPVAXIVE is a conjugate vaccine in which polysaccharides from 21 Streptococcus pneumoniae serotypes are individually conjugated to diphtheria CRM₁₉₇ carrier protein, a mechanism shared with other licensed PCVs. It was originally designed with an adult-focused serotype profile: It includes 8 serotypes (15A, 15C, 16F, 23A, 23B, 24F, 31, and 35B) not contained in any other approved pneumococcal vaccine while omitting some serotypes present in PCV15 and PCV20, including serotypes 1, 5, and 6B.¹

The FDA first approved CAPVAXIVE on June 17, 2024, for adults aged 18 years and older for prevention of IPD and pneumococcal pneumonia, based on four phase 3 trials demonstrating robust immunogenicity in both vaccine-naïve and vaccine-experienced adults.^1,2 The pneumonia prevention indication remains under accelerated approval, contingent upon verification of clinical benefit in a confirmatory trial. The current pediatric approval follows the same accelerated-approval framework for the pneumonia end point.

References:

1. U.S. FDA approves an additional indication for CAPVAXIVE (pneumococcal 21-valent conjugate vaccine) in children and adolescents aged 2 through 17 years at increased risk for pneumococcal disease. News release. Merck. June 18, 2026. Accessed June 18, 2026. https://www.merck.com/news/u-s-fda-approves-an-additional-indication-for-Capvaxive-pneumococcal-21-valent-conjugate-vaccine-in-children-and-adolescents-aged-2-through-17-at-increased-risk-for-pneumococcal-disease/

2. A clinical study of the V116 vaccine for children and teenagers (V116-013) (STRIDE-13). ClinicalTrials.gov. NCT06177912. Updated March 24, 2025. Accessed June 2026. https://clinicaltrials.gov/study/NCT06177912

3. Grainger EM, Waight PA, Andrews NJ, Miller E, Ladhani SN. Invasive pneumococcal disease after 2 decades of pneumococcal conjugate vaccine use. Pediatrics. 2024;153(1):e2023063039. doi:10.1542/peds.2023-063039