To protect infants, FDA advisers recommend RSV vaccine during pregnancy

Members of an FDA advisory panel voted in support of Pfizer’s respiratory syncytial virus (RSV) vaccine (Abrysvo) for the prevention of RSV in infants via administration to pregnant women.

The panel’s 14 advisers unanimously deemed the vaccine effective, while 10 out of 14 said the vaccine was safe. A study by Pfizer indicated that premature delivery was reported in 5.6% of pregnancies in the treatment group compared with 4.7% in the placebo group.

FDA officials said the difference was not statistically significant, but Pfizer said if the drug gets approved it would track health records for cases of preterm birth and other potential health issues. However, advisers expressed doubt about a plan to use health care billing records data to monitor safety.

CDC estimates that up to 80,000 children younger than age 5 years are hospitalized with RSV each year, and up to 300 die from RSV. The vaccine was tested in approximately 7,300 pregnant people after the 24th week of pregnancy, with about one-half receiving the vaccine and one-half receiving a placebo.

A recent study in NEJM found that during the first 90 days after birth, six infants in the vaccination group contracted a severe case of RSV compared with 33 in the placebo group, indicating an efficacy of almost 82%. For 6 months after birth, the vaccine was found to be 69% effective. During that time, there were 19 babies who became seriously ill in the treatment group compared with 62 in the placebo group.