Photo: 123rfMiddlemore Hospital has been involved in global research into a vaccine for pregnant mothers against the RSV virus. Respiratory syncytial virus (RSV) causes infections in the lungs and respiratory tracts. The clinical trial used a vaccine developed by Pfizer for pregnant mothers, which was designed to help boost the immunity of their children after birth. But the study's findings show pregnant mothers can greatly reduce the risk of their infants being hospitalised with RSV if they were given the trial vaccine during pregnancy. "It's taken a very long time to get an RSV vaccine we can use to prevent severe infections in infants," she said.