HIV Infection Boosted by Washing the Penis Soon After Having Sex

Well, cleaning the penis minutes after sex does not wash away the HIV. On the contrary, for uncircumcised men, it even increases the risk of getting infected.

The team at the Makerere University Institute of Public Health made the research on 2,552 uncircumcised, HIV-negative men aged 15 to 29 from the Rakai district, Uganda. 83 % of the subjects told they washed their penises with all sex partners.

They were asked when and how they washed their penises, even if they washed it with or without clothes, at the start of the research and at 6, 12 and 24 months after that. Still, the researchers did not questioned the subjects about the type of used soap, and this is an important issue, as some African soaps are more irritating than soaps coming from other places.

Men who washed within 3 minutes after sex had a 2.3% risk of HIV infection, while those who delayed washing 10 minutes or more had a risk of just 0.4%. Scientists believe that delaying washing means a longer exposure to vaginal secretions, that could be involved in lower viral infectivity.

The vaginal secretions have a low pH (under 7 or acid) and this decreases HIV's survival capacity on the penis, while water has a neutral pH, around 7, increasing HIV's survival and the man's possible infection. "HIV likely needs to be in a fluid to cross the mucosa and infect cells. If HIV-infected fluid dries, its infectivity could decrease.", said co-author Ronald Gray, professor of population and family planning at Johns Hopkins Bloomberg School of Public Health.

Thus, soaking the penis with water reactivates the HIV. "There ought to be a little time left for postcoital cuddling before you go and wash. Don't just finish and jump out of bed.", added Gray.

"The findings are counterintuitive and show why you have to do the studies, because until you do them, you just don't know. There is still so much we don't understand about the complex factors that influence HIV transmission in the genital tract, but this important study will help," said Merle Sande, an infectious disease expert at the University of Washington-Seattle and president of the Academic Alliance Foundation, that trains health workers to treat HIV/AIDS and other infectious diseases in Uganda.