Oral HIV Prophylaxis May Also Provide Some Protection Against Herpes

Connie Celum, MD, MPH Professor of Global Health and Medicine Director, International Clinical Research Center University of Washington Harborview Medical Center Seattle WA  98104MedicalResearch.com: Interview with
Connie Celum, MD, MPH
Professor of Global Health and Medicine
Director, International Clinical Research Center
University of Washington
Harborview Medical Center
Seattle WA  98104

MedicalResearch: What are the main findings of the study?

Dr. Celum: We conducted a randomized, double blind study of daily oral tenofovir and tenofovir combined with emtricitabine (FTC) as oral pre-exposure prophylaxis (PrEP) for HIV among HIV serodiscordant couples (in which onepartner had HIV and the other partner did not) in Kenya and Uganda. Because of recent studies showing that tenofovir gel could reduce the chances of becoming HSV-2 infected, we studied the subset of HIV-uninfected partners who did not have HSV-2 and compared the rates who became HSV-2 infected during follow-up among those  who received oral pre-exposure prophylaxis versus those who received placebo.  We found that oral pre-exposure prophylaxis reduced HSV-2 acquisition by 30%.


MedicalResearch: Were any of the findings unexpected?

Dr. Celum: Tenofovir has greater activity against HIV than HSV-2, and we had previously reported that tenofovir reduced HIV acquisition by 67% and tenofovir combined with emtricitabine by 75%.  It was not known whether oral dosing of tenofovir would achieve sufficient levels to provide protection against HSV-2.

MedicalResearch: What should clinicians and patients take away from your report?

Dr. Celum: HSV-2 is the most common cause of genital herpes.  About 20% of adults in the US have HSV-2 infection and about 50% of adults in Africa.  HSV-2 prevalence is higher among women than men and higher among those who have HIV infection.  Previous studies have indicated that HSV-2 increases the risk of becoming HIV infected by about 2 fold, and thus is an important co-factor for HIV. Given that HSV-2 is  common, HSV-2 increases the risk of acquiring and transmitting HIV, and additional HSV-2 prevention strategies are needed, it is beneficial that oral tenofovir can reduce the risk of acquiring HSV-2 as well as HIV.  Thus, we have shown that tenofovir and tenofovir combined with emtricitabine (Truvada) PrEP has high efficacy against becoming HIV infected and provides partial protection against acquiring HSV-2.

MedicalResearch: What recommendations do you have for future research as a result of this study?

Dr. Celum: Tenofovir is being studied for pre-exposure prophylaxis in a vaginal and rectal microbicide gel and in an intravaginal ring, which provide higher levels than with oral dosing.  It will be important to see if these formulations provide protection against HSV-2.  In addition, because tenofovir is often part of HIV treatment, it is important to study whether it reduces the risk of HIV infected persons getting HSV-2 infection, which is being studied.

Citation:

Celum C, Morrow RA, Donnell D, Hong T, Hendrix CW, Thomas KK, et al. Daily Oral Tenofovir and Emtricitabine–Tenofovir Preexposure Prophylaxis Reduces Herpes Simplex Virus Type 2 Acquisition Among Heterosexual HIV-1–Uninfected Men and Women: A Subgroup Analysis of a Randomized Trial. Ann Intern Med. 2014;161:11-19.

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