CAPVAXIVE (PCV21), manufactured by Merck, was approved by the FDA through an accelerated approval process, in June 2024. According to the manufacturer, in adults 50 years and older, PCV21 targets approximately 84 percent of the pneumococcal serotypes associated with invasive pneumococcal disease (IPD) and 85 percent of serotypes associated with IPD in adults 65 years and older.
Clinical trials of PCV21 did not study the vaccine’s efficacy or effectiveness. Like with other pneumococcal conjugate vaccines, immune responses (immunogenicity) were measured and compared against other licensed vaccines. PCV21 compared immune responses to those of PCV20, and were reported by Merck to be non-inferior in the 10 serotypes contained in both vaccines, and superior in 10 of the 11 serotypes unique to PCV21. There are, however, no established corelates of protection that ensure an individual is protected from invasive pneumococcal disease.
No data is available on whether PCV21 will have any impact on the rates of invasive pneumococcal disease in adults.
