Environmental factors affecting the transmission of respiratory viruses

Many viruses are capable of infecting the human respiratory tract to cause disease. These viruses display various transmission patterns among humans; however, they all share the ability to transmit from person to person, and their human transmissibility is influenced by the environment in which pathogen and host meet. This review aims to summarize recent and significant observations regarding the impact of environmental factors such as weather and climate, humidity, temperature, and airflow on the transmission of human respiratory viruses. Where possible, knowledge gaps that require further scientific study will be identified.

► Respiratory viruses are spread from person to person via various modes of transmission, including direct and indirect contact, droplet spray, and aerosol.
► Virus transmission is affected by a number of factors, including environmental determinants, host behavior, host defense mechanisms, and virus infectivity.
► Uncertainties remain with respect to the relative importance of these factors and the roles that they play.