Merck Presents Findings From Systematic Literature Review Of Studies On Epidemiology And AMR Of Pneumococcal Serotypes Covered By CAPVAXIVE In U.S. Adults, At IDWeek 2025

Author: Benzinga Newsdesk | October 21, 2025 06:48am

Findings presented at IDWeek 2025 underscore the importance of considering serotypes that disproportionately impact adults in the U.S. and show greater resistance to commonly prescribed antibiotics

Merck (NYSE:MRK), known as MSD outside of the United States and Canada, today announced the presentation of findings from a systematic literature review of studies on the epidemiology and antimicrobial resistance (AMR) of pneumococcal serotypes covered by CAPVAXIVE® (Pneumococcal 21-valent Conjugate Vaccine) in U.S. adults. The evaluation examined 15 studies published between 2015 and 2025 to assess the serotype-specific burden of pneumococcal disease (PD) associated with serotypes covered by CAPVAXIVE but not PCV20 (pneumococcal 20-valent conjugate vaccine) (CAPVAXIVE-unique serotypes: 9N, 15A, 15C, 16F, 17F, 20A, 23A, 23B, 24F, 31, 35B) compared to serotypes covered by PCV20 but not CAPVAXIVE (PCV20-unique serotypes: 1, 4, 5, 6B, 9V, 14, 18C, 19F, 23F). Findings were presented at IDWeek 2025 in Atlanta, GA.

A total of 15 full-text publications from the U.S., in addition to CDC Active Bacterial Core (ABC) Surveillance reports, were included in the analysis. Of these 15, 13 reported prevalence, five reported incidence, two reported mortality, two reported AMR, one reported health resource utilization (HRU) and PD complications. Results of this systematic literature review showed that CAPVAXIVE-unique serotypes are more prevalent in U.S. adults with PD than PCV20-unique serotypes. Based on two of the publications, PD caused by CAPVAXIVE-unique serotypes have higher rates of resistance to commonly prescribed antibiotics used to treat non-invasive PD. Specific findings from the systematic review of the studies include:

• As of 2023, the ABC data indicated that in older adults (≥65 years), the prevalence of invasive PD attributed to CAPVAXIVE-unique serotypes was more than triple (34.8%) that of PCV20-unique serotypes (8.5%). Among adults 50-64 years old, the prevalence of CAPVAXIVE-unique serotypes was ~30%, vs ~15% for PCV20-unique serotypes;
• Among hospitalized adults (≥18 years) from 2009-2017, AMR was reported for seven of the CAPVAXIVE-unique serotypes and one of the PCV20-unique serotypes;
• Among hospitalized adults (≥18 years) in studies where AMR was reported, penicillin and erythromycin resistance were higher for serotypes 35B (96% and 89%) and 23A (72% and 46%). Multidrug resistance rates were highest for serotypes 19F (42%) and 23A (27%). Serotype 19F is covered by PCV20; serotypes 35B and 23A are covered by CAPVAXIVE.

CAPVAXIVE is indicated in the U.S. for:

• Active immunization for the prevention of invasive disease and pneumonia caused by Streptococcus pneumoniae serotypes 3, 6A, 7F, 8, 9N, 10A, 11A, 12F, 15A, 15B, 15C, 16F, 17F, 19A, 20A, 22F, 23A, 23B, 24F, 31, 33F and 35B in individuals 18 years of age and older;
• Active immunization for the prevention of pneumonia caused by S. pneumoniae serotypes 3, 6A, 7F, 8, 9N, 10A, 11A, 12F, 15A, 15C, 16F, 17F, 19A, 20A, 22F, 23A, 23B, 24F, 31, 33F and 35B in individuals 18 years of age and older.

CAPVAXIVE should not be administered to individuals with a history of a severe allergic reaction (e.g., anaphylaxis) to any component of CAPVAXIVE or to diphtheria toxoid; see additional Select Safety Information below.

The indication for the prevention of pneumonia caused by S. pneumoniae serotypes 3, 6A, 7F, 8, 9N, 10A, 11A, 12F, 15A, 15C, 16F, 17F, 19A, 20A, 22F, 23A, 23B, 24F, 31, 33F and 35B is approved under accelerated approval based on immune responses as measured by opsonophagocytic activity (OPA). Continued approval for this indication may be contingent upon verification and description of clinical benefit in a confirmatory trial.

CAPVAXIVE is currently approved in the U.S., European Union, Japan and many other countries around the world. Specifically designed for adults, CAPVAXIVE helps provide coverage against the serotypes responsible for approximately 84% of invasive pneumococcal disease (IPD) cases in adults 50 years of age and older, compared to approximately 52% covered by PCV20, based on national-level CDC ABC surveillance data from 2018-2022, representing ~35 million persons and 10 states across the US. Regional variations may exist. CAPVAXIVE includes eight unique serotypes not covered by other currently approved pneumococcal vaccines; those serotypes were responsible for approximately 27% of IPD cases in adults 50 years of age and older and approximately 30% in adults 65 years of age and older, based on the same CDC data. These values do not reflect the efficacy of the respective vaccines, and there are currently no studies comparing the efficacy of CAPVAXIVE and PCV20.

Posted In: MRK