When a positive virus test turns negative, it is not contagious. After a person with a viral infection has been treated or cured himself, he undergoes the relevant test and the result is negative, which means that the virus in the organism has been cleared, so it is not infectious, that is to say, it will not transmit the disease any more. Some of the more common viruses, such as the new coronavirus and hepatitis B virus, are highly contagious because the body has the virus. The new coronavirus, in particular, can be transmitted directly through droplets or even aerosols, but after the virus is removed from the body through treatment, it is no longer contagious. The new coronavirus is highly contagious, it is recommended to wear a mask when going out, stay away from crowded places and take personal protection seriously.