Clinical Trial Info

A Trial to Evaluate the Efficacy and Safety of RSVpreF in Infants Born to Women Vaccinated During Pregnancy

Authored by
Last Reviewed
November 2, 2022

This is a Phase 3, multicenter, randomized, double-blinded, placebo-controlled study to assess the efficacy, safety, and immunogenicity of RSVpreF or placebo (1:1 randomization) in infants born to 10,000 healthy women vaccinated during pregnancy, as well as the safety and immunogenicity in the pregnant women.

This will be a global study that will span multiple RSV seasons.


Pfizer announced positive top-line data from the MATISSE (MATernal Immunization Study for Safety and Efficacy).

RSVpreF vaccine was well-tolerated with no safety concerns for vaccinated women and their newborns.

The observed efficacy for severe medically attended lower respiratory tract illness (severe MA-LRTI) was 81.8% (CI: 40.6%, 96.3%) through the first 90 days of life. Substantial efficacy of 69.4% (CI: 44.3%, 84.1%) was demonstrated for infants over the six-month follow-up period.