Why Do Gay Men Have an Increased Risk of HIV?

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Around the world, the incidence of HIV in gay men is startlingly consistent. It hovers between 2 and 5 percent. The U.S. transmission rate declined in the early years of the American epidemic. That was when activists were promoting condoms. It was also a time when HIV was constantly in the news. However, more recently HIV has been getting much less attention. Possibly related to this, transmission rates have begun to creep up again.

The sexual HIV transmission rate in men who have sex with men (MSM) is substantially higher than the rate seen in men who primarily have sex with women. Why? The increased risk MSM experience reflects a number of biological, behavioral, and social factors.

  • The average HIV transmission rate during anal sex is estimated to be 18 times higher than the rate during vaginal intercourse. The risk of acquiring HIV during an act of unprotected anal intercourse is estimated to be 1.4 percent. 
  • The role variability of gay men increases transmission risk. Role variability refers to taking different "roles" during sexual encounters. Men who practice receptive, unprotected anal intercourse are at higher risk of contracting HIV. Men who practice insertive, unprotected anal intercourse are more likely to transmit HIV to their partners. This combination optimizes the spread of HIV between gay men in a way not seen in heterosexual couples. In heterosexual couples, men are far more likely to penetrate and women to be penetrated. Because of this, HIV is far more likely to spread from the male partner to the female partner than vice versa. 
  • Homophobia against gay men makes it more difficult for them to access health care. Other forms of legal and social discrimination affect their access as well. Problems getting care may cause delays in diagnosis and treatment of HIV infection. That's really unfortunate. People are often most infectious during acute (new) infection, and treatment reduces infectivity. Therefore, delaying healthcare further increases the HIV risk among MSM.

    In addition, certain groups of gay men are at particularly high risk another reason. Their risk is high because a large percentage of their potential partners are infected with the virus. This  is particularly problematic for black MSM. They often date within very small, high-risk communities. As such, their HIV risk is often higher than that of other MSM. That's true even when their behavioral and lifestyle choices are safer.

    For example, black MSM in the United States are three times as likely to have HIV as other MSM, That's true even though, on average, they are less likely to engage in risky behaviors. For example, they are less likely to use drugs during sex. However, it's not just the higher risk of their partner pool that causes this disparity. Compared to other HIV positive MSM, black MSM with HIV are also less likely to:

    • have health insurance
    • be on successful cART regimens
    • have a high CD4 count 

    This reflects systemic healthcare inequities related to race. Those effects are not limited to HIV or to black MSM.

    Did You Know: Around the world, most sexually transmitted cases of HIV are spread through heterosexual intercourse. 

    Addressing the Stigma That Makes People Call AIDS a Gay Disease

    There was an eye-opening article published in the July 2012 special issue of The Lancet.

    That issue was called "HIV in Men who have Sex with Men." In a game-changing bit of research, Dr. Chris Beyrer and colleagues calculated that 80-90 percent of the HIV epidemic in gay men would disappear if the transmission rate during anal intercourse was the same as it is during vaginal intercourse. Role segregation could also drop the numbers by 20-50 percent. Putting those two things together might get rid of as many as 95 percent of the HIV infections seen in gay men. In other words, it's not primarily behavior that puts gay men at such high risk of HIV. It's biology. 

    Increased access to non-judgmental healthcare would help as well.Imagine a world where gay men felt safe disclosing their sexual risk to their doctors.

    That could make a big difference. They might get tested more frequently. Then they could treated sooner. In turn, early treatment would reduce the risk of men infecting their partners as well as improving their health. Unfortunately, the CDC's recommendation of universal HIV testing (for everyone, not just gay men) hasn't had a big enough effect. Very few doctors and clinics have actually been following the rules.

    Fortunately, there are signs that things may be improving. When powerful data was released showing that reducing viral load reduces the likelihood of sexual transmission of HIV, policies changed. Both New York and San Francisco started recommending  universal access to HIV treatment. They removed  restrictions related to CD4 count that meant HIV positive individuals had to wait to start treatment. This change could be a great boon to serodiscordant gay couples. Reducing an infected partner's viral load is not only a form of treatment. It also helps keep their lover safe from infection. The discovery of this effect, known as "treatment as prevention" continues to reshape HIV policy in the U.S. It is also changing the way doctors and scientists look at HIV prevention around the world. 

    Sources:

    Beyrer, C., Baral, S.D., vanGriensven, F. Goodreau, S.M., Chariyalerstak, S., Wirtz, A., & Brookmeyer, R. (2012) Global epidemiology of HIV infection in men who have sex with men. The Lancet. 380(9839):367-377
    Millett, G.A., Peterson, J.L., Flores, S.A., Hart, T.A., Jeffries, W.L., Wilson, P.A., Rourke, S.B., Heilig, C.M., Elford, J., Fenton, K.A>, & Remis, R.S. (2012) Comparisons of disparities and risks of HIV infection in black and other men who have sex with men in Canada, UK, and USA: a meta-analysis. The Lancet. 380(9839):341-348

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