People with genital herpes must take caution to avoid infecting partner

Ask Dr. Keith Roach M.D

DEAR DR. ROACH: I am a 75-year-old male in excellent health who is sexually active. During my thirties, I was exposed to the herpes virus 2, but recurrences now are extremely rare and mild. Even so, I use a condom during sexual intercourse and also take acyclovir beforehand. How long before intercourse should acyclovir be taken so that it is at high strength? If I take two 400-mg tablets instead of one, will that improve protection? Will acyclovir by itself provide enough protection so that a condom is not necessary? Finally, if my female partner takes acyclovir, will that help increase protection? — Anon. ANSWER: There are conflicting answers to your questions, but here is my summary: People with any history of genital herpes are at risk of shedding infectious virus, which can potentially infect a partner who has never had it. Although people with lesions (such as painful blisters) are much more infectious, people with no symptoms at all can transmit the virus. Many people with genital herpes don’t even know they have it. Acyclovir, like its more potent cousin, valacyclovir (Valtrex), suppresses viral shedding — but the suppression isn’t complete, and takes about five days for maximum effectiveness. Valacyclovir reduced overall days of shedding (and therefore potential infectivity) from 11% of days to 3% of days. The studies I found to suppress shedding used acyclovir 400 mg twice daily. In couples where one person had genital herpes and the other didn’t, chronic suppression did not reduce the likelihood of the uninfected partner getting herpes, but this study was done in people with HIV, who likely have a higher risk of infecting their partner. Condoms reduce transmission of genital herpes by about 30%. Your partner taking medication to prevent infection (called pre-exposure prophylaxis) makes some sense; however, I could find no good data to show how effective it might be. Because of these factors, your female partner should understand that despite you doing everything you can, she is still at risk of acquiring genital herpes, so she should be aware of that fact prior to initiating sexual activity. *** Dr. Roach regrets that he is unable to answer individual letters, but will incorporate them in the column whenever possible. Readers may email questions to ToYour-GoodHealth@med.cornell. edu or send mail to 628 Virginia Dr., Orlando, FL 32803.