Merck & Co. said it won US approval for a shot that protects against RSV, the most common cause of hospitalization among infants.

The U.S. Food and Drug Administration on Monday approved Merck's preventive antibody shot to protect infants up to one year of age from respiratory syncytial virus during their first RSV season, the company said.

The Food and Drug Administration has approved a new drug from Merck designed to protect infants from respiratory syncytial virus, or RSV, a common but potentially serious seasonal illness.