Advisers to the U.S. Food and Drug Administration (FDA) will discuss Pfizer Inc’s experimental respiratory syncytial virus (RSV) vaccine on Thursday. If approved, it would be the first available maternal shot to protect babies from RSV, a virus that can cause severe illness in infants.
The FDA staff reviewers deemed the safety data for Pfizer’s vaccine “generally favorable” and the shot was 82% effective in a late-stage trial in preventing severe RSV infections in infants when given to expecting mothers in the second half of their pregnancy.
Development of RSV vaccines has picked up pace in recent years after researchers were able to better understand the virus’ structure and maintain a type of protein found on its surface in a form that could activate the body’s immune response. Sanofi and AstraZeneca’s antibody drug nirsevimab is also under FDA review to prevent RSV in infants.
If Pfizer’s vaccine is approved by the FDA, the U.S. Centers for Disease Control and Prevention will then need to sign off on its use to make it widely available to pregnant mothers.