A data analysis released today by the Centers for Disease Control and Prevention underscores the disproportionate impact of HIV and syphilis among gay and bisexual men in the United States.
The data, presented at CDC's 2010 National STD Prevention Conference, finds that 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 range was 522-989 cases of new HIV diagnoses per 100,000 MSM vs. 12 per 100,000 other men and 13 per 100,000 women.
The rate of primary and secondary syphilis among MSM is more than 46 times that of other men and more than 71 times that of women, the analysis says. The range was 91-173 cases per 100,000 MSM vs. 2 per 100,000 other men and 1 per 100,000 women.
While CDC data have shown for several years that gay and bisexual men make up the majority of new HIV and new syphilis infections, CDC has estimated the rates of these diseases for the first time based on new estimates of the size of the U.S. population of MSM. Because disease rates account for differences in the size of populations being compared, rates provide a reliable method for assessing health disparities between populations.
"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, M.D., director of CDC's National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention. "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."
For the purposes of determining rates of disease for MSM, CDC researchers first estimated the size of the gay and bisexual male population in the United States -- defined as the proportion of men who reported engaging in same-sex behavior within the past five years. Based on an analysis of nationally representative surveys, CDC estimated that MSM comprise 2.0 percent (range: 1.4-2.7 percent) of the overall U.S. population aged 13 and older, or 4 percent of the U.S. male population (range: 2.8-5.3 percent). Disease rates per 100,000 population were then calculated using 2007 surveillance data on HIV and primary/secondary syphilis diagnoses and U.S. Census data for the total U.S. population.
The new analysis is the first step in more fully assessing the impact of HIV among MSM and other populations significantly affected by the disease. CDC is developing more detailed estimates of infection rates among MSM by race and age, as well as among injection drug users. CDC is also in the early stages of planning for estimates among heterosexuals. Ultimately, these data can be used to better inform national and local approaches to HIV and STD prevention to ensure that efforts are reaching the populations in greatest need.
Research shows that a range of complex factors contribute to the high rates of HIV and syphilis among gay and bisexual men. These factors include high prevalence of HIV and other STDs 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 (e.g., oral sex). Additionally, factors such as homophobia and stigma can prevent MSM from seeking prevention, testing, and treatment services.
Also, the risk of HIV transmission through receptive anal sex is much greater than the risk of transmission via other sexual activities, and some gay and bisexual men are relying on prevention strategies that may be less effective than consistent condom use.
"There is no single or simple solution for reducing HIV and syphilis rates among gay and bisexual men," said Fenton. "We need intensified prevention efforts that are as diverse as the gay community itself. 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."
Preventing HIV and STDs among gay and bisexual men is a top CDC priority. CDC provides funding to health departments and community-based organizations throughout the nation to implement proven behavior-change programs for MSM and will soon expand a successful HIV testing initiative to reach more gay and bisexual men. Additionally, CDC is implementing an updated National Syphilis Elimination Plan in cities where MSM have been hardest hit by the disease, and will release an updated HIV prevention strategic plan within the next year to support the President's upcoming National HIV/AIDS Strategy. CDC officials note that the new analysis released today underscores the importance of the HIV and STD prevention efforts targeting gay and bisexual men recently announced as part of the President's fiscal year 2011 budget proposal.
For more information on HIV or syphilis, please visit www.cdc.gov/hiv or www.cdc.gov/std.