The NY Times
reports that the study found that the sooner the washing occurred, the greater the risk becoming infected with HIV.
On the other hand, delaying washing by 10 minutes after sex lowered the risk.
They do not have a definitive explanation as to why. These findings challenge the common wisdom about washing to beat infectious disease. Health experts have suggested that washing the penis after sex could in fact prevent potential infectious vaginal secretions from entering the body through the uncircumcised penis.
In Africa, washing the penis after sex is common. They wanted to see if washing could be a good alternative to male circumcision, so they studied 2,552 uncircumcised men in the Rakai district of Uganda ages 15 to 49. They were uncircumcised and free of HIV infection when they joined the study.83% said they washed with all sex partners.
They were asked about when and how they washed after sex when they enrolled. Asked again 6, 12 and 24 months later, including whether they washed with or without cloths.
There was however a slip-up. They did not ask directly how the cleaning was done or about soap use, which is important because some soaps in Africa are more irritating then those used elsewhere.
Men who washed within 3 minutes of sex had a 2.3 risk of infection compared to .04 for those who delayed it 10 minutes or longer.
One message from the study, Dr. Gray said, “is that there ought to be a little time left for post coital cuddling before you go and wash.”
“Don’t just finish and jump out of bed,” he said.
They have no idea why, but they have some thoughts. One is that the acidity of vaginal secretions may impair the ability of the AIDS virus to survive on the penis. Which makes sense and might explain why delayed cleansing reduces the risk.
It is also possible that use of water, which has a neutral pH, may encourage the survival of the virus.
H.I.V. apparently needs to be in a fluid to cross the mucosa to infect cells, Dr. Gray said. If the H.I.V.-contaminated fluid dries, its infectivity may decrease. Adding water could re suspend H.I.V. to make it more infectious.
This is very a fascinating study, with unanswered questions. The important part here is that they now have clues to follow.