A Peru based study found that daily treatment with the anti-herpes drug valaciclovir significantly reduced HIV viral load in both the blood and genital secretions of HIV/herpes simplex virus-2- infected men who have sex with men (MSM).

Although safe sex may decrease the risk of transmission of some STIs, there are other significant ways in which STIs can be transmitted. Herpes and HPV (the virus associated with genital warts) can be transmitted even if condoms are used. Hepatitis A, gut and bowel infections, and the virus that is thought to be associated with Kaposi’s Sarcoma can be passed on through rimming.