Can you be infected with HSV and not know it?

Yes. Many individuals who give no history of HSV infection are seropositive for HSV-specific antibodies. Using viral culture or PCR, HSV can periodically be recovered from the mouth and/or anogenital region of such individuals (see “asymptomatic shedding” above). Based on the seroprevalence of herpes-specific antibody, 70% to 80% of the population is infected with HSV-1 and 25% to 30% with HSV-2. It is estimated that out of every four individuals with genital herpes, three do not know they are infected.

Xu F, Sternberg MR, Kottiri BJ, et al: Trends in herpes simplex virus type 1 and type 2 seroprevalence in the United States, JAMA 296:964–973, 2006.