RSV vaccine meta‑analysis

Respiratory syncytial virus is a common virus, but in infants it can inflame the small airways and send babies to the hospital. A new meta-analysis found that vaccinating pregnant women cut severe infant cases and RSV-related hospitalizations after birth. (nature.com) The review, published April 13, 2026 in the *Journal of Perinatology*, pooled six randomized controlled trials with 18,011 pregnant women and 17,769 infants. The authors compared maternal RSV vaccines with placebo and combined the results with a random-effects model. (nature.com) Across those trials, maternal vaccination was linked to a 65% lower risk of severe RSV-associated lower respiratory tract infection in infants within 180 days of birth, with a pooled risk ratio of 0.35. RSV-related hospitalization was also lower, with a pooled risk ratio of 0.53. (nature.com) Lower respiratory tract infection means infection in the lungs and small breathing tubes, not just a cold in the nose or throat. The study also found fewer medically attended RSV lower respiratory tract infections, but that estimate was imprecise and did not clearly rule out no effect, with a pooled risk ratio of 0.47 and a 95% confidence interval of 0.18 to 1.21. (nature.com) The safety question has been central to RSV vaccination in pregnancy because an earlier vaccine program raised concern about preterm birth, meaning delivery before 37 weeks. In this review, the pooled estimate did not show a safety signal for preterm birth, with a risk ratio of 1.15 and a 95% confidence interval of 0.95 to 1.38. (nature.com) The authors also reported no safety signal for low birth weight or congenital malformations in the pooled trial data. Their conclusion was that maternal RSV vaccination reduced severe infant RSV disease with what they called a reassuring perinatal safety profile. (nature.com) The basic idea behind maternal vaccination is straightforward: the pregnant woman makes antibodies, and those antibodies cross the placenta before birth. The Centers for Disease Control and Prevention says that protection can then help cover a baby during the first RSV season, when the youngest infants face the highest risk. (cdc.gov) In the United States, the Centers for Disease Control and Prevention recommends one dose of Pfizer’s Abrysvo during 32 through 36 weeks of pregnancy, usually from September through January in most of the country. The agency says most infants will not need both maternal vaccination and an infant RSV antibody product. (cdc.gov) The Food and Drug Administration label for Abrysvo says the vaccine should be given at 32 through 36 weeks of gestation to avoid the potential risk of preterm birth with use before 32 weeks. The label also lists the most common reactions in pregnant individuals as injection-site pain, headache, muscle pain, and nausea. (fda.gov) Obstetricians now have two infant-protection paths to discuss during RSV season: maternal vaccination before delivery or a monoclonal antibody for the baby after birth. The American College of Obstetricians and Gynecologists says clinicians should clarify that if a patient declines maternal RSV vaccination, the infant should receive a monoclonal antibody instead. (acog.org)