MadSci Network: Virology

Re: Re: Is there any scientific proof that gay males are at a higher HIV risk?

Date: Tue Nov 4 11:12:52 2008
Posted By: Michel Ouellet,
Area of science: Virology
ID: 1209283817.Vi

Yes there is a scientific reason but in my own opinion, it should not be sufficient to refuse you as a blood donor. A simple HIV blood test could show that you are seronegative and if you are not sexually active with men anymore, your risk is the same as other heterosexual men or women. If you are still sexually active with other men, then your risk is in fact much higher and it is possible that the FDA has decided to exclude this risk group to minimize the risk to blood receivers. Of course, the decision of the FDA is based on multiple epidemiological and biological factors that have the objective to protect the blood banks and thus the population against blood-borne pathogens. It is certainly possible that testing for HIV every male blood donor who had sex with another male since 1977 would be cost prohibitive and that asking for a blood test would require too much administration to be cost effective. Money is thus certainly a factor also.

Here are what I think could be the scientific reasons:

First, do not dismiss the statistics altogether as they are representative of the behavior, transmission rates and biology of the virus and the population it infects. Do not forget that although they seem to be just numbers, each number represent one very real individual. Although the infection has spread a lot to the heterosexual community, the prevalence of HIV infection amongst homosexuals/bisexuals, especially men who have sex with men, is still much higher and increasing much faster than in the heterosexuals.

This is mainly because of general behavioral issues such as protection and having multiple partners . Now, I'm not saying that all bi/homosexuals cannot have a stable relationship but it is less common than for heterosexuals in the general population.

Another important issue is transmission rates. Genital-anal sexual relations have a much higher risk of HIV transmission than oro-genital or genital-genital sexual relations. Why is the risk of transmission higher?

The lining of the rectum is much more delicate than the lining of the vagina, it is thus more prone to show micro-tears following sexual intercourse. The lining of the rectum is the first and most important barrier to HIV infection and any injury means that it cannot protect against HIV anymore. The infection rate is thus much higher. From 1:100 per unprotected sexual act for anal-genital, it goes down to 1:200 for infected man to healthy woman genital relations to 1:500 infected woman to healthy man genital relation.

The risk is thus higher for women who have sex with an infected man than a man with an infected woman. The higher risk, however, is for a man who have sex with an infected man. Keep in mind that although the actual risk per unprotected sexual act seems low, a 1 in 500 chance of catching a fatal disease is not one I would take. Of course, it is important to know that all these risks could be decreased by nearly a 100-fold just by the use of a condom.

You could take a look at the following references: ordinalpos=3&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_DefaultReportPanel .Pubmed_RVDocSum 6852570210054fc3e/$FILE/HIV%20TRANSMISSION%20Guidelines%20for%20assessing%20risk.pdf SexualActivity.pdf

Have a good day,

Michel Ouellet, Ph.D.
Retrovirology and Immunology

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