When are viruses no longer contagious?

Answer 1

According to the article linked in the related links section below:

A cold is contagious for at least a day before you come down with the symptoms. During that time you may be transmitting the cold virus to all of your buddies and co-workers even when you're feeling fine. Once you come down with the symptoms, a cold is contagious until the last of your symptoms go away.

However, the author points out that the virus is most contagious when viral levels in your body are highest, so it is highly contagious before symptoms appear or when they first start appearing, but much less contagious 3-4 days after the first appearance of symptoms, as your immune system will have killed off most of the virus by then. The author recommends,

If you're considering calling in to work, it's a good idea for at least the first three to four days when a cold is most contagious. If you're still sniffling and coughing at the end of that time period, you'll likely still be somewhat contagious, but less so. If you go to work, it's important to use a tissue to cover your mouth when you cough or sneeze and avoid contact with others as much as possible. Your employees will thank you for your kind consideration.

Answer 2

The medical term for the condition "shingles" is herpes-zoster and it's caused by the varicella-zoster virus, or VZV. VZV is a member of the herpesvirus family and is responsible for both chicken pox (initial infection) and herpes zoster (reactivated infection).

VZV is no longer contagious once the open blisters have crusted over and there's no more drainage. Understand that h. zoster isn't contagious. This is a condition that results when VZV is reactivated. If some one who has not previously been exposed to VZV should transmit this virus to his own respiratory tract, this person would contract chicken pox, not h. zoster. H. zoster cannot occur unless a person has first had chicken pox. The virus must already be in the system and because VZV belongs to the herpesvirus family, it will remain in the body for life.

Answer 3

Studies show that, if you contract a cold, you can transmit it to others one or two days before your symptoms appear, and up to four or five days after first being exposed to the virus. According to the National Institutes of Health (NIH), colds are most contagious two to four days after original exposure (whether or not symptoms have developed), when there is plenty of the virus present in nasal secretions.

Answer 4

A cold sore is contagious up to about 14 days after the sore heals.
Cold sores are most contagious when there is an active sore that is in the weeping stage; and it can be contagious for up to 21 days after the weeping begins.
Always.

There are small traces of the Herpes virus present in body fluids. Usually not enough for contagion.

It is very contagious when it is inflamed. No kissing please.

Answer 5

It is healed after the scab goes away and there are no more flare ups.

Answer 6

Cold sores are no longer contagious when the sores have dried and crusted completely. Until then, the herpes virus is contagious.

Answer 7

The area is completely healed in about 2 weeks after the sore is gone.