Merck said on Tuesday an antibody-based drug met the main goal of a mid-to-late stage trial testing it as a therapy to protect infants from disease caused by the respiratory syncytial virus.

The drug, MK-1654, helped reduce the incidence of lower respiratory infection in infants compared to placebo, and met the safety goals of the study, Merck said.

RSV is a contagious virus that can lead to serious respiratory conditions such as pneumonia. According to the company, it causes an estimated 101,000 deaths a year worldwide in children under five.