RSV (respiratory syncytial virus) is a virus that infects the lungs and airways (breathing passages). RSV can affect anyone of any age, but it's most common in infants and young children. In fact, it's so common that almost all children have been infected with RSV by the age of three.
RSV is usually a mild disease that goes away on its own. In very young children RSV can sometimes lead to serious infections like pneumonia or bronchiolitis (a swelling of the bronchioles — the smallest air passages of the lungs).
When do people usually get RSV?
RSV usually happens in outbreaks starting in late fall through early spring. Outbreaks usually peak during the winter months.