Transmission
Respiratory syncytial virus (RSV) is highly contagious. It is transmitted through direct contact with nasal secretions of infected individuals. RSV is also stable on environmental surfaces, such as doorknobs, toys, and hands, for several hours—making it easily spread in school classrooms and daycare centers and easily brought home to other children in the home. The time between infection and the appearance of symptoms is about 4 to 6 days.
RSV does not induce complete immunity against future infections, so people can get RSV multiple times—even during a single season. The first infection is usually the most severe. Repeat infections are generally associated with milder symptoms.