The Centers for Disease Control and Prevention (CDC) has recommended the use of Pfizer’s maternal vaccine, Abrysvo, to protect infants from respiratory syncytial virus (RSV). The shot is advised for expectant mothers between 32 to 36 weeks into their pregnancy from September through January to safeguard their children against RSV, which is the leading cause of hospitalization among U.S. infants.
This recommendation follows an 11 to 1 vote by an independent panel of advisors to the CDC. The decision aligns with the CDC’s efforts to address RSV and other respiratory viruses that have been spreading more in the U.S., particularly after an intense RSV season last year.
Pfizer’s Abrysvo initially approved for adults aged 60 and above, is the first RSV vaccine to use maternal immunization. Pregnant mothers receive the shot, which generates antibodies passed on to the fetus, providing protection from birth through the first six months of life. The FDA set the 32- to 36-week dosing timeframe when approving the vaccine.
The CDC advisory panel weighed data from a phase three trial involving nearly 7,400 participants. During the first 90 days post-birth, the vaccine was nearly 82% effective at preventing severe RSV disease and 57% effective at reducing RSV-related doctor’s visits. The effectiveness slightly decreased over time, with the vaccine being about 70% effective at preventing severe disease and 51% effective at avoiding doctor’s visits by six months post-birth.
While Pfizer’s vaccine showed efficacy, there were concerns about potential safety risks. The trial indicated a slightly higher rate of premature births among mothers receiving the shot compared to those given a placebo. Pfizer will conduct a post-marketing study to examine the risk of premature births and pregnancy-related complications following vaccination.
The CDC’s recommendation provides another tool to combat RSV during the fall and winter seasons, benefiting infants and pregnant women.