Which virus is most often associated with cold sores?

The virus most often associated with cold sores is the Herpes simplex virus. Specifically, it is typically the type known as HSV-1, which is commonly responsible for oral and facial herpes. Cold sores, also referred to as fever blisters, are lesions that commonly appear on or around the lips and are triggered by the reactivation of the virus, often following periods of stress, illness, or sun exposure.

Herpes simplex virus establishes latency in the body after the initial infection, which means that even when symptoms subside, the virus remains in the body and can reactivate, leading to recurrent outbreaks of cold sores. This characteristic of latency and reactivation is what makes HSV-1 the primary virus linked to cold sore development, distinguishing it from the other viruses listed, which do not have this association with cold sores.