Cold sores are contagious from the moment you feel that first tingling until the scar completely disappears, a process that usually takes about 15 days. The Mayo Clinic notes that cold sores are most contagious when oozing blisters are present, but you can still transmit the virus even if there is no active sore.

Can you kiss someone with a cold sore and not get it?

Truth: You can get a cold sore by kissing.

Even if you don't see the sores, the virus can still be contagious. But you should be especially cautious about kissing someone who has active blisters, because that's when the virus spreads most easily.

Are cold sores contagious when not visible?

You can spread the virus even when you don't have any symptoms of a cold sore, though you're usually most contagious when you have them. However, this is much less likely than if contact occurred when a cold sore was present. Cold sores are contagious until they go away completely, which usually takes about two weeks.