How effective are pneumococcal conjugate vaccines at preventing pneumococcal carriage or disease?

FDA licensed the first pneumococcal conjugate vaccine against seven serotypes (PCV7, Prevnar7, Pfizer) in 2000. A large clinical trial showed PCV7 reduced invasive disease caused by vaccine serotypes by 97%. Compared to unvaccinated children, children who received PCV7:

• Had 20% fewer episodes of chest X-ray confirmed pneumonia
• Had 7% fewer episodes of acute otitis media
• Underwent 20% fewer tympanostomy tube placements

FDA licensed PCV13 based on studies comparing the serologic response of children who received PCV13 to those who received PCV7. Substantial evidence demonstrates that routine infant PCV7 and PCV13 vaccination reduces the carriage and transmission of vaccine serotypes.

Researchers conducted a randomized placebo-controlled trial (CAPiTA trial) in the Netherlands among approximately 85,000 adults 65 years or older from 2008 through 2013. This trial evaluated the clinical benefit of PCV13 in the prevention of pneumococcal pneumonia. The results of the CAPiTA trial demonstrated:

• 46% efficacy against vaccine-type pneumococcal pneumonia
• 45% efficacy against vaccine-type non-bacteremic pneumococcal pneumonia
• 75% efficacy against vaccine-type invasive pneumococcal disease (IPD, i.e., bacteremia or meningitis)

FDA licensed PCV15 and PCV20 in 2021 based on studies comparing the serologic response of adults who received either PCV15 or PCV20 to those who received PCV13. These studies showed PCV15 and PCV20 induced antibody levels comparable to those induced by PCV13 and shown to be protective against invasive disease. FDA subsequently expanded the indication for use of PCV15 and PCV20 to include children starting at age 6 weeks in 2022 and 2023, respectively, based on serologic studies. PCV21 was licensed in 2024 based on a similar evaluation of serologic response to vaccination.