Background

Respiratory viruses account for most respiratory infections. Although analysis of epidemiologic information regarding viral seasonality, sites of transmission and susceptible populations is essential to devising strategies for limiting epidemics, few long term epidemiologic studies have addressed these questions.

Methods

Epidemiologic findings identifying susceptible populations, as well as temporal and geographic patterns of infection with influenza virus, respiratory syncytial virus, rhinovirus and parainfluenza virus were reviewed.

Conclusions

Influenza is the virus most frequently associated with outbreaks of respiratory infection resulting in medical consultation as well as virus-related lethality. Similar symptom profiles and overlapping seasonality of respiratory syncytial virus and other viruses may sometimes complicate surveillance and treatment. Although vaccination and antiviral drugs are virus-specific, factors that promote transmission and thus strategies for limiting outbreaks are similar for various respiratory viruses.