Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.
Virus, environmental and host factors influence whether a successful transmission occurs by governing the infectivity of the respiratory virus, the contagiousness of the infected person, the environmental stress on the virus, which affects its persistence and survival during transmission, and the susceptibility of the exposed person.
