On Nov. 1, 2022, Pfizer announced positive top-line data from the Phase 3 clinical trial (NCT04424316) MATISSE (MATernal Immunization Study for Safety and Efficacy) investigating its bivalent RSV prefusion vaccine candidate, RSVpreF or PF-06928316, when administered to pregnant participants to help protect their infants from RSV disease after birth.

The pre-planned, interim efficacy analysis conducted by an external and independent Data Monitoring Committee met the success criterion for one of two primary endpoints.