Public Health Impact

Data from several U.S. cities and projects, including syphilis outbreak investigations and the Gonococcal Isolate Surveillance Project (GISP) suggest that an increasing number of men who have sex with men (MSM) are acquiring STDs.^1-7 Data also suggest that an increasing number of MSM are engaging in sexual behaviors that place them at risk for STDs and HIV infection.⁸ Several factors may be contributing to this change, including the availability of highly active antiretroviral therapy (HAART) for HIV infection.⁹ Because STDs and the behaviors associated with acquiring them increase the likelihood of acquiring and transmitting HIV infection,¹⁰ the rise in STDs among MSM may be associated with an increase in HIV incidence among MSM.¹¹

Observations

Most nationally notifiable STD surveillance data reported to CDC do not include information regarding sexual behaviors; therefore, national trends in STDs among MSM in the United States are not currently available. Data from enhanced surveillance projects are presented in this section to provide information regarding STDs in MSM.

Monitoring Trends in Prevalence of STDs and HIV Risk Behaviors among Men Who Have Sex with Men (MSM Prevalence Monitoring Project), STD Clinics, 1999–2005

From 1999 through 2005, nine U.S. cities participating in the MSM Prevalence Monitoring Project submitted syphilis, gonorrhea, chlamydia, and HIV test data to CDC from 107,370 MSM visits to STD clinics; data from 89,998 MSM visits were submitted from six public STD clinics (Denver, Long Beach, New York City, Philadelphia, San Francisco, and Seattle) and data from 17,372 MSM visits were submitted from three STD clinics in community-based, gay men's health clinics (Chicago, the District of Columbia, and Houston). In 2005, eight U.S. cities submitted information from 18,455 MSM STD clinic visits.

The MSM Prevalence Monitoring Project includes data from culture and non-culture tests collected during routine care and reflects testing practices at participating clinics. City-specific medians and ranges were calculated for the proportion of tests done and STD and HIV test positivity.

Gonorrhea

From 1999 to 2005 the number of gonorrhea tests for all anatomic sites combined has increased in all eight cities. The trend in the number of positive gonorrhea tests for all anatomic sites has varied by city. For all cities, the number of symptomatic positive gonorrhea tests accounts for the majority of the overall positive tests (Figure W).

In 2005, 78% (range: 57-95%) of MSM were tested for urethral gonorrhea, 26% (range: 3-69%) were tested for rectal gonorrhea, and 26% (range: 4-87%) were tested for pharyngeal gonorrhea.

In 2005, median clinic urethral gonorrhea positivity in MSM was 11% (range: 8-14%), median rectal gonorrhea positivity was 8% (range: 4-10%), and median pharyngeal gonorrhea positivity was 7% (range: 1-21%).

Syphilis

In 2005, 79% (range: 60-92%) of MSM visiting participating STD clinics had a nontreponemal serologic test for syphilis (STS) [RPR or VDRL] performed compared with 69% (range: 54-93%) in 1999.

Overall, median syphilis seroreactivity among MSM tested increased from 4% (range: 4-13%) in 1999 to 11% (range: 5-13%) in 2005 (Figure X).

Chlamydia

In 2005, a median of 78% (range: 58-94%) of MSM visiting participating STD clinics were tested for urethral chlamydia; median urethral chlamydia positivity was 6% (range: 5-8%).

HIV Infection

In 2005, a median of 68% (range: 31-82%) of MSM visiting STD clinics in the project and not previously known to be HIV-positive were tested for HIV; median HIV positivity was 4% (range: 3-7%). HIV positivity varied by race/ethnicity, but was higher in African-American and Hispanic MSM. HIV positivity was 3% (range: 2-4%) in whites, 7% (range 3-12%) in African Americans, and 7% (range: 3-10%) in Hispanics (Figure Y).

In 2005, median HIV prevalence among MSM, including persons previously known to be HIV-positive and persons testing HIV-positive at their current visit, was 12% (range 9-15%). HIV prevalence was 10% (range: 7-13%) in whites, 20% (range: 15-27%) in African Americans, and 15% (range: 7-20%) in Hispanics.

STDs by Race/Ethnicity

In 2005, by race/ethnicity, urethral gonorrhea positivity was 11% (range: 7-13%) in whites, 15% (range: 9-23) in African Americans, and 9% (range: 6-15%) in Hispanics. Rectal gonorrhea positivity was 8% (range: 4-11%) in whites, 4% (range: 2-7%) in African Americans, and 8% (range: 4-11%) in Hispanics.

Pharyngeal gonorrhea positivity was 5% (range: 1-12%) in whites, 8% (range: 1-9%) in African Americans, and 4% (range: 1-10%) in Hispanics (Figure Y).

Median syphilis seroreactivity was 9% (range: 3-12%) in whites; 14% (range: 9-32%) in African Americans, and 14% (range: 4-19%) in Hispanics (Figure Y).

Urethral chlamydia was 6% (range: 4-8%) in whites; 7% (range: 3-15%) in African Americans, and 6% (range: 3-8%) in Hispanics (Figure Y).

STDs by HIV Status, STD Clinics, 2005

In 2005, by HIV status, urethral gonorrhea positivity was 18% (range:15-27) in HIV-positive MSM and 9% (range 7-14%) in MSM who were HIV-negative or of unknown HIV status; rectal gonorrhea positivity was 10% (range: 6-19%) in HIV-positive MSM and 7% (range: 3-9%) in MSM who were HIV-negative or of unknown HIV status; pharyngeal gonorrhea positivity was 6% (range: 1-11%) in HIV-positive MSM and 6% (range: 1-20%) in MSM who were HIV-negative or of unknown HIV status (Figure Z).

Median syphilis seroreactivity was 23% (range: 18-43%) in HIV-positive MSM and 8% (range: 3-12%) in MSM who were HIV-negative or of unknown HIV status (Figure Z).

Median urethral chlamydia positivity was 7% (range: 5-10%) in HIV-positive MSM and 6% (range: 5-8%) in MSM who were HIV-negative or of unknown HIV status (Figure AA).

Nationally Notifiable Syphilis Surveillance Data

Primary and secondary (P&S) syphilis increased in the United States between 2001 and 2005, with a 78.6% increase in the number of P&S syphilis cases among men and a 31.9% decrease in the number of cases among women (Tables 25 and 26). In 2005, the rate of reported P&S syphilis among men (5.1 cases per 100,000 males) was 5.7 times greater than the rate among women (0.9 cases per 100,000 females) (Figure S, Table 23). Trends in the syphilis male-to-female rate ratio, which are assumed to reflect, in part, syphilis trends among MSM,⁷ have been increasing in the United States during recent years (Figure 33). The overall male-to-female syphilis rate ratio has risen steadily from 2.1 in 2001 to 5.7 in 2005 (Figure 33, Tables 25 and 26). The increase in the male-to-female rate ratio occurred among all racial and ethnic groups between 2001 and 2005. Additional information on syphilis can be found in the Syphilis section (National Profile).

Gonococcal Isolate Surveillance Project (GISP)

The Gonococcal Isolate Surveillance Project (GISP), a collaborative project among selected STD clinics, was established in 1986 to monitor trends in antimicrobial susceptibilities of strains of Neisseria gonorrhoeae in the United States.¹²

GISP also reports the percentage of N. gonorrhoeae isolates obtained from MSM. Overall, the proportion of isolates from MSM in GISP clinics has been increasing steadily from 4% in 1988 to 20.2% in 2004 and now 21.9% in 2005, with most of the increase occurring after 1993 (Figure AA). Additional information on GISP may be found in the Gonorrhea section (National Profile).

The proportion of isolates coming from MSM varies geographically with the largest percentage from the West Coast (Figure BB).

Due to increases in the proportion of N. gonorrhoeae isolates from MSM that are quinolone-resistant (Figure 25), in 2006 CDC recommended that quinolones no longer be used to treat gonorrhea among MSM.^13,14

¹ Centers for Disease Control and Prevention. Gonorrhea among men who have sex with men – selected sexually transmitted disease clinics, 1993–1996. MMWR 1997;46:889-92.

² Centers for Disease Control and Prevention. Resurgent bacterial sexually transmitted disease among men who have sex with men – King County, Washington, 1997–1999. MMWR 1999;48:773-7.

³ Centers for Disease Control and Prevention. Outbreak of syphilis among men who have sex with men – Southern California, 2000. MMWR 2001;50:117-20.

⁴ Fox KK, del Rio C, Holmes K, et. al. Gonorrhea in the HIV era: A reversal in trends among men who have sex with men. Am J Public Health 2001;91:959-964.

⁵ Centers for Disease Control and Prevention. Primary and secondary syphilis among men who have sex with men – New York City, 2001. MMWR 2002;51:853-6.

⁶ Centers for Disease Control and Prevention. Primary and secondary syphilis – United States, 2003–2004. MMWR 2006;55:269-73.

⁷ Beltrami JF, Shouse RL, Blake PA. Trends in infectious diseases and the male to female ratio: possible clues to changes in behavior among men who have sex with men. AIDS Educ Prev 2005;17:S49-S59.

⁸ Stall R, Hays R, Waldo C, Ekstrand M, McFarland W. The gay '90s: a review of research in the 1990s on sexual behavior and HIV risk among men who have sex with men. AIDS 2000;14:S1-S14.

⁹ Scheer S, Chu PL, Klausner JD, Katz MH, Schwarcz SK. Effect of highly active antiretroviral therapy on diagnoses of sexually transmitted diseases in people with AIDS. Lancet 2001;357:432-5.

¹⁰ Fleming DT, Wasserheit JN. From epidemiologic synergy to public health policy and practice: the contribution of other sexually transmitted diseases to sexual transmission of HIV infection. Sex Transm Infect 1999;75:3-17.

¹¹ Centers for Disease Control and Prevention. HIV/AIDS Surveillance Report, 2003, (Vol. 15). Atlanta: U.S. Department of Health and Human Services, Centers for Disease Control and Prevention; 2004.

¹² Centers for Disease Control and Prevention. Sexually Transmitted Disease Surveillance 2005 Supplement: Gonococcal Isolate Surveillance Project (GISP) Annual Report 2005. Atlanta, GA: U.S. Department of Health and Human Services (available first quarter 2007).

¹³ Centers for Disease Control and Prevention. Increases in fluoroquinolone-resistant Neisseria gonorrhoeae among men who have sex with men – United States, 2003, and revised recommendations for gonorrhea treatment, 2004. MMWR 2004;53:335-338.

¹⁴ Centers for Disease Control and Prevention. Sexually Transmitted Diseases Treatment Guidelines, 2006. MMWR, 2006;55(No. RR-11).