Novavax RSV vaccine given to mothers shows positive effect on infants.

Biotechnology company Novavax Inc said data from a mid-stage study showed that immunizing pregnant women with its RSV vaccine was effective in protecting infants from the virus.

The trial tested the vaccine against a placebo in 50 healthy pregnant women in their third trimester.

Women who received placebo showed no significant change in their antibody levels, the company said.