A Phase III, Randomized, Double-blind, Placebo-controlled Multi-country Study to Demonstrate Efficacy of a Single Dose of Unadjuvanted RSV Maternal Vaccine, Administered IM to Pregnant Women 18 to 49 Years of Age, for Prevention of RSV Associated LRTIs in Their Infants up to 6 Months of Age

The purpose of this study was to evaluate the ability of a single dose of the investigational RSV Maternal vaccine, administered intramuscularly (IM) to pregnant women aged 18-49 years, in good general maternal health, in preventing medically assessed RSV associated Lower Respiratory Tract Illnesses (LRTIs) in infants born to vaccinated mothers. The study also evaluated the safety of the investigational RSV Maternal vaccine both in vaccinated mothers and in their corresponding infant.Following a recommendation from the Independent Data Monitoring Committee of NCT04605159 (RSV MAT 009), GSK made the decision to stop enrolment and vaccination in the study. Ongoing study participants at that time continued to be monitored as part of the study.