U.S. regulators on Monday approved the first RSV vaccine for pregnant women so their babies will be born with protection against the respiratory infection, according to the Associated Press.
RSV is notorious for filling hospitals with sick babies every fall and winter. The Food and Drug Administration cleared Pfizer’s maternal vaccination to guard against a severe case of RSV when babies are most vulnerable — from birth through six months of age.
The next step is for the Centers for Disease Control and Prevention to issue recommendations for using the vaccine, named Abrysvo, during pregnancy. Vaccinations for older adults, also at high risk, are getting underway this fall using the same Pfizer shot plus another from competitor GSK.
RSV is a coldlike nuisance for most healthy people but it can be life-threatening for the very young. It inflames babies’ airways so it’s hard to breathe or causes pneumonia. In the U.S. alone, between 58,000–80,000 children younger than five are hospitalized each year, and several hundred die, from the respiratory syncytial virus.
Last year’s RSV season was extremely harsh in the U.S., and it began sickening babies in the summer, far earlier than usual.
Pfizer’s study included nearly 7,400 pregnant women and their babies. Maternal vaccination didn’t prevent mild RSV infection, but it proved 82% effective at preventing a severe case during babies’ first three months of life. At age six months, it still was proving 69% effective against severe illness.
Vaccine reactions were mostly injection-site pain and fatigue. In the study, there was a slight difference in premature birth — just a few weeks early — between vaccinated moms and those given a dummy shot, something Pfizer has said was due to chance. The FDA said to avoid the possibility, the vaccine should be given only between 32 weeks and 36 weeks of pregnancy, a few weeks later than during the clinical trial.
If enough pregnant women get vaccinated, Pfizer has predicted the U.S. could prevent as many as 20,000 infant hospitalizations a year and 320,000 doctor visits.
Another option for protecting infants from RSV is giving them lab-made antibodies. The FDA recently approved a new drug that’s the first one-dose version, recommended for all infants younger than 8 months before their first RSV season starts. Beyfortus, from Sanofi and AstraZeneca, is expected to be available this fall.
