Following a confusingly constructed press release from the University of Pittsburgh, multiple media outlets have erroneously reported that the risk of HIV for bisexual men in the United States is comparable to the risk for heterosexual men. The incorrect reports, in outlets including Medical Daily and WebMD, essentially turn on a confusion between the number of HIV infections among hetero- versus homosexuals, and the rate of infection in each respective group.

Presenting their findings at the American Public Health Association’s 141st Annual Meeting & Exposition in Boston, researchers from the University of Pittsburgh Graduate School of Public Health conducted meta-analyses of 31 scientific articles that provided data on HIV prevalence and risk among men who have sex with men only (gay) and men who have sex with both men and women (bisexual).

The investigators found that bisexual men had an HIV prevalence rate 60 percent lower than that of gay men. They theorized that this difference in HIV prevalence was because bisexual men were also 60 percent less likely than gay men to report unprotected receptive anal intercourse.

Bisexuals, they estimated, have an HIV prevalence rate of about 10 percent: Out of an estimated 1.2 million bisexual men in the United States, 121,800 are HIV positive. A similar number of heterosexual men are living with HIV.

Here is where the media reports got confused: The reports state that the risk of HIV is the same for both bisexual and heterosexual men. But this would only be true if the rate of HIV were the same between the two groups. What is only the same between the two groups is the number of cases. Because there are vastly more heterosexual than bisexual men in the country, the rate of HIV infection for straight men is therefore a small fraction of that of bisexual men’s.

The university’s release states that the notion of viral “bridging,” in which bisexual men contract HIV from men and then transmit to women, has been “exaggerated.” (The study abstract puts this more equivocally, calling the notion “relatively overstated.”) However, the release does not clarify whether this exaggeration is a consequence of misunderstandings about the true number of bisexuals, the number of bisexuals living with HIV, or the rate of HIV among bisexuals as it compares with either gay men or heterosexuals.

Both the WebMD and Medical Daily stories also inaccurately state that the researchers conducted an analysis of over 3,000 studies to reach their conclusions. In fact, the investigators reviewed 3,474 articles in order to come up with the 31 papers they ultimately used in their analysis. While the study abstract clarifies this important difference, the university press release is vague, only stating that the researchers "reviewed over 3,000 scientific articles" for the study.

In an email exchange with POZ and AIDSmeds, Allison Hydzik, a University of Pittsburgh Schools of the Health Sciences spokesperson, acknowledged the inaccuracies in the news reports and added that neither Medical Daily nor WebMD had contacted the school for clarification.  

Hydzik defended the university’s release, stating, “The press release was not intended to mislead anyone, and the facts it presents are an accurate reflection of the research. The release was intended to bring attention to this important research, which highlights the need for national, bisexual-specific data collection and funding for HIV prevalence research in bisexual men. Such data is important in prevention, testing and treatment outreach efforts.”

To read the Medical Daily story, click here.

To read the WebMD stork, click here.

To read the study abstract, click here.

To read the University of Pittsburgh release on the study, click here.