STD Quarterly

Report outlines impact of syphilis and HIV in U.S. gay and bisexual men

Rate of new HIV diagnoses among MSM is 44 times that of other men

An analysis presented at the 2010 National STD Prevention Conference gives a chilling look at impact of HIV and syphilis among U.S. gay and bisexual men.1 The rate of new HIV diagnoses among men who have sex with men (MSM) is more than 44 times that of other men and more than 40 times that of women. The rate of primary and secondary syphilis among MSM is estimated at more than 46 times that of other men and more than 71 times that of women.

"While the heavy toll of HIV and syphilis among gay and bisexual men has been long recognized, this analysis shows just how stark the health disparities are between this and other populations," said Kevin Fenton, MD, director of the Centers for Disease Control and Prevention's (CDC) National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention, upon the release of the new information. "It is clear that we will not be able to stop the U.S. HIV epidemic until every affected community, along with health officials nationwide, prioritize the needs of gay and bisexual men with HIV prevention efforts."

While CDC data have shown for several years that gay and bisexual men make up most new HIV and new syphilis infections, the new rates reflect estimates based on the size of the U.S. population of gay and bisexual men. Because disease rates account for differences in the size of populations being compared, the new rates provide a reliable method for assessing health disparities between populations.

The analysis is just a first step in outlining the scope of the challenge, says Jennifer Horvath, a CDC spokesperson. The federal agency also is developing further breakdowns of MSM rates by race and age, as well as estimates for other populations significantly affected by HIV, such as injection drug users, she notes.

Look at the numbers

To determine the rates of disease for men who have sex with men, CDC researchers first estimated the size of the gay and bisexual male population in the United States, which is defined as the proportion of men who reported engaging in same-sex behavior within the past five years. By analyzing nationally representative surveys, the researchers conclude that MSM comprise 2.0% (range: 1.4-2.7%) of the overall U.S. population ages 13 and older, or 4% of the U.S. male population (range: 2.8-5.3%).

Disease rates per 100,000 population then were calculated using 2007 surveillance data on HIV and primary/secondary syphilis diagnoses and U.S. Census data for the total U.S. population.1The analysis reports the range of new HIV diagnoses in MSM was 522-989 cases per 100,000, versus 12 per 100,000 other men and 13 per 100,000 women. The rate of primary and secondary syphilis among MSM was calculated at more than 46 times that of other men and more than 71 times that of women. The range was 91-173 cases per 100,000 MSM versus 2 per 100,000 other men and 1 per 100,000 women.

"These data underscore the significant disparities in HIV and syphilis among gay and bisexual men, and this new analysis calls for the need to intensify efforts to address the diverse profile of HIV in the gay community," says Horvath. "These results should also prompt a wake-up call that we will not be able to stop the U.S. HIV epidemic until every community more fully addresses the prevention needs of gay and bisexual men."

What's the next step?

The CDC recently has announced the expansion of its successful HIV testing initiative to reach more gay and bisexual men with HIV testing services.

Funding for the new phase of the initiative is expected to total about $142.5 million over the next three years. It will be provided to state and local health departments across the country to increase access to testing and early diagnosis of HIV. While the initiative originally was designed to increase testing and knowledge of HIV status primarily among African-American men and women, the program now will reach more U.S. jurisdictions and populations at risk. These include gay and bisexual men, as well as male and female Latinos and injection drug users. Public health officials are focusing the funding on areas across the nation where these populations are hardest hit. (Federal officials set a June 3, 2010, deadline for funding applications. Go to the CDC web page for more information.)

"Far too many Americans with HIV -- more than 200,000 people -- are unaware of their infection and may be unknowingly transmitting the virus to others," said Jonathan Mermin, MD, director of CDC's Division of HIV/AIDS Prevention, in an announcement of the program expansion. "The expansion of this initiative reflects CDC's continued commitment to ensure that far more Americans are tested for HIV, especially among vulnerable men and women most in need of HIV services."

To address the challenge of syphilis's impact in the gay and bisexual male community, the CDC is looking to increase access to syphilis screening for MSM, especially among those with HIV infection, says Horvath. The agency also continues to implement its updated National Syphilis Elimination Plan to address increases in syphilis diagnoses among MSM and prioritize prevention in cities where such men have been hardest hit, she notes.

"CDC provides funding to the health departments with the greatest burden of syphilis cases, which in turn focus their efforts on the populations most impacted by the disease in their local areas," says Horvath. "CDC is also partnering with health departments and community-based organizations to expand testing, treatment, and prevention among MSM."

Multiple avenues eyed

Many factors come into play when looking at the high rates of HIV and syphilis among gay and bisexual men, research suggests.

These factors include high prevalence of HIV and other sexually transmitted diseases among MSM, which increases the risk of disease exposure, and limited access to prevention services. Other factors are complacency about HIV risk, particularly among young gay and bisexual men; difficulty of consistently maintaining safe behaviors with every sexual encounter over the course of a lifetime; and lack of awareness of syphilis symptoms and how it can be transmitted, such as in oral sex.2Additionally, factors such as homophobia and stigma can prevent gay and bisexual men from seeking prevention, testing, and treatment services, research indicates.

There is no single or simple solution for reducing HIV and syphilis rates among gay and bisexual men, says Fenton.

"We need intensified prevention efforts that are as diverse as the gay community itself," he says. "Solutions for young gay and bisexual men are especially critical, so that HIV does not inadvertently become a rite of passage for each new generation of gay men."


  1. Purcell DW, Johnson C, Lansky A, et al. Calculating HIV and syphilis rates for risk groups: estimating the national population size of men who have sex with men. Presented at the 2010 National STD Prevention Conference. Atlanta; March 2010.
  2. Ciesielski CA. Sexually transmitted diseases in men who have sex with men: an epidemiologic review. Curr Infect Dis Rep 2003; 5:145-152.