Respiratory syncytial virus (RSV) is a common virus that causes infections of the upper and lower respiratory airways (including the nose, sinuses and lungs). Discovered in 1956, RSV is a ribonucleic acid (RNA) virus that belongs to the family Paramyxoviridae. It is classified into 2 subgroups, RSV-A and RSV-B. Both subgroups tend to co-circulate during each season and both can cause severe disease.

Source: Respiratory syncytial virus, WHO