Question: If I Have Cold Sores (HSV1) Am I Protected Against Genital Herpes (HSV2)?
Answer: It's unlikely. There has not been a lot of published research discussing whether or not infection with HSV-1 (usually associated with oral infection) provides any protection against HSV-2 (usually associated with genital infection), but what research there is suggests that infection with one strain of the herpes virus is NOT protective against infection with the other. One study that was designed to directly research the question found that HSV-1 infection was not protective against HSV-2 infection. Individuals with HSV-1 were just as likely to acquire HSV-2 as their HSV-1 negative counterparts; however, a previous oral herpes infection did increase the likelihood of a newly acquired genital herpes infection being asymptomatic - i.e. not having any symptoms. This makes sense since many people are infected with both strains of the virus, and it is possible to transmit either of the two herpes viruses to their less preferred sites during oral sex. In fact, HSV-1 is accounting for more and more cases of genital herpes as time goes on.
Sources:
Langenberg A.G.M. et al. "A PROSPECTIVE STUDY OF NEW INFECTIONS WITH HERPES SIMPLEX VIRUS TYPE 1 AND TYPE 2" New England Journal of Medicine. 1999;341:1432-8.
Haddow L.J. et al. "Increase in rates of herpes simplex virus type 1 as a cause of anogenital herpes in western Sydney, Australia, between 1979 and 2003."
Sex Transm Infect. 2006; 82(3):255-9.
