When Are Cold Sores Most Contagious?

Cold sores are considered to be most contagious when the blisters have burst open and have begun to weep fluid.

This is because the liquid held in these blisters contains literally millions of herpes simplex virus particles.

During an outbreak, the population of virus particles becomes less and less as the cold sore runs its course.

There is a much smaller amount of virus particles present when the sore is healing and when the scab has formed.

However, as there are still virus particles present throughout every phase of the cold sore outbreak the infected area is still considered to be contagious until the skin has completely healed.

If you know that you have come into contact with the virus in the past few minutes or so (e.g. If you or your partner have just touched an infected area) the simple action of washing your hands and the infected area with soap and warm water can help to sweep away the virus from your hands and other areas.

By doing this you can help avoid the virus from spreading further.