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Can I get HIV through oral sex?
May 29, 2009
Can I get HIV through oral sex? is probably one of the most frequent questions we get. The answer is yes, possibly, but it is exceptionally unlikely.
There has been a great deal of interest and many research papers written about the HIV risks associated with oral sex and similarly many studies to try to determine why the risk of oral sex with an HIV positive person might be less than that associated with unprotected penetrative vaginal or anal sex.
Romero and others, in their article describing an excellent and diligent long term study failed to identify any risk at all in transfer of HIV from an HIV positive to an HIV negative partner through oral sex. In total 19000 episodes of oral sex were documented amongst 135 heterosexual couples over ten years and in 34% of these episodes the HIV positive male ejaculated into the HIV negative females' mouth. (Romero J et al. Evaluating the risk of HIV transmission through unprotected orogential sex. AIDS 16:9:1269-97, 2002.)
Baggaley and others, in their article Systematic review of orogenital HIV-1 transmission probabilities. International Journal of Epidemiology 37 : 1255-65, 2008 have reviewed the major articles to date and conclude that the risks of HIV transmission via oral sex are low.
To reach their conclusions they conducted a systematic review of the available literature. Ten studies from North America and Europe were identified as meeting the required criteria.
The authors noted some difficulties with the methodology of the studies. These were mainly the common ones of:-
• People rarely confining their sexual activity to oral sex alone
• where people have had other sorts of sex including unprotected anal or vaginal penetration it is assumed that the higher risk activity will have given them HIV
• exact details of the sexual activity have been missed out - ie whether or not ejaculation into the mouth etc
• Studies where one partner is known to be HIV positive and the other HIV negative are likely to be slightly skewed because the HIV positive person is likely to be on anti-retroviral medications and consequently probably less infectious anyway.
The overall conclusion was that:-
• Chances of acquiring HIV through oral sex with an HIV infected partner are very low. The majority of the studies reporting zero to miniscule risk.
• Very large, very expensive, well controlled studies would be needed to define the question exactly.
The results of a study due to appear shortly in AIDS seem to show that HIV negative gay males in sero-discordant ( a relationship where one of the partners is HIV positive and the other HIV negative) relationships have saliva which has an HIV neutralising capacity. Consequently one of the conclusions drawn is that repeated exposure to low levels of HIV may produce a level of resistance to HIV in this population.