"To carry the virus" means to have a virus inside your body without showing any signs or symptoms of being sick. You can pass the virus to others without realizing it.
Sentences with «to carry the virus»
Some cats carry the virus for years without having any symptoms at all. (cat-health-guide.org)
Humans can also carry the virus on their shoes, clothing, hands, etc.. (petairapy.com)
Dogs can sometimes carry the virus without signs of illness, and pass it to other dogs in social settings such as parks. (thesprucepets.com)