Respiratory syncytial virus vaccination during pregnancy and effects in infants

The purpose of the Prepare Study Group was to determine whether maternal vaccination prevents babies from developing severe lower respiratory tract infection caused by respiratory syncytial virus (RSV) in the first 90 days of life.

The purpose of the Prepare Study Group was to determine whether maternal vaccination prevents babies from developing severe lower respiratory tract infection caused by respiratory syncytial virus (RSV) in the first 90 days of life. The researchers worked with a sample of 4,636 healthy women who were at least 28 weeks into gestation but not more than 36 weeks. All had due dates near the onset of RSV season. Each participant was randomized to receive either an intramuscular dose of RSV fusion (F) protein nanoparticle vaccine or placebo. Among 4,579 live births, medically significant RSV-associated lower respiratory tract infection presented within 90 days in 1.5% of babies in the vaccine group and 2.4% of infants in the control group. The difference was not considered statistically significant; however, possible benefits related to other outcomes underscore the need for additional research.