Public Health Impact

Data from several U.S. cities and projects, including syphilis outbreak investigations and the GISP suggest that an increasing number of MSM are acquiring STDs.^1-7 Data also suggest that an increasing number of MSM engage 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 diagnoses 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, HIV and Risk Behaviors among Men Who Have Sex with Men (MSM Prevalence Monitoring Project), STD Clinics, 1999-2006

From 1999 through 2006, eight U.S. cities participating in the MSM Prevalence Monitoring Project submitted syphilis, gonorrhea, chlamydia, and HIV test data to CDC from 120,164 MSM visits to STD clinics; data from 98,866 MSM visits were submitted from five public STD clinics (Denver, New York City, Philadelphia, San Francisco, and Seattle) and data from 21,298 MSM visits were submitted from three STD clinics in community-based, gay men's health clinics (Chicago, the District of Columbia, and Houston).

Changes in testing technology for gonorrhea and chlamydia have occurred in recent years with the advent of nucleic acid amplification tests (NAATs) which achieve greater sensitivity than traditional culture methods.^12,13 The MSM Prevalence Monitoring Project includes data from culture and non-culture tests collected during routine care and reflects testing practices at participating clinics. Tests for gonorrhea included culture, NAATs, or nucleic acid hybridization tests (DNA probes). Tests for chlamydia included culture, NAATs, DNA probes, or direct fluorescent antibody tests (DFAs). Nontreponemal syphilis tests included the Rapid Plasma Reagin (RPR) test and the Venereal Disease Research Laboratory (VDRL).

All statistics were based on data collected from clinic visits and may reflect multiple visits by a patient rather than individual patients. City-specific medians and ranges were calculated for the proportion of tests done and for STD and HIV test positivity.

Gonorrhea

Between 1999 and 2006 the number of gonorrhea tests for all anatomic sites combined increased in all eight cities. The trend in the number of positive gonorrhea tests for all anatomic sites 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 2006, 75% (range: 56-94%) of MSM were tested for urethral gonorrhea, 40% (range: 3-61%) were tested for rectal gonorrhea, and 53% (range: 6-87%) were tested for pharyngeal gonorrhea.

In 2006, median clinic urethral gonorrhea positivity in MSM was 10% (range: 8-13%), median rectal gonorrhea positivity was 7% (range: 2-13%), and median pharyngeal gonorrhea positivity was 7% (range: 1-15%).

Chlamydia

In 2006, a median of 75% (range: 58-93%) of MSM visiting participating STD clinics were tested for urethral chlamydia, compared to 65% (range: 58-68%) in 1999. In 2006, the median urethral chlamydia positivity was 6% (range: 5-8%).

Syphilis

In 2006, 83% (range: 61-94%) of MSM visiting participating STD clinics had a nontreponemal serologic test for syphilis (RPR or VDRL) performed, compared with 69% (range: 54-93%) in 1999 (Figure X).

Overall, median seroreactivity among MSM tested for syphilis increased from 4% (range: 4-13%) in 1999 to 10% (range: 6-18%) in 2006.

Syphilis seroreactivity is used to estimate syphilis prevalence and is correlated with prevalence of P&S syphilis in this population.¹⁴

HIV Infection

Trends - Overall, the percent of MSM tested for HIV in STD clinics increased between 1999 and 2006. In 2006, a median of 73% (range: 28-85%) of MSM visiting STD clinics that were not previously known to be HIV-positive were tested for HIV, while 44% (range: 21-55%) were tested in 1999. In 2006, median HIV positivity in MSM was 4% (range: 2-7%) (Figure Y).

In 2006, 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: 10-16%).

HIV/STDs by Race/Ethnicity

HIV positivity varied by race/ethnicity, but was highest in African-American MSM. HIV positivity was 3% (range: 1-4%) in whites, 10% (range: 3-13%) in African Americans, and 4% (range: 2-6%) in Hispanics.

HIV prevalence was 11% (range: 7-16%) in whites, 21% (range: 15-25%) in African Americans, and 14% (range: 8-19%) in Hispanics.

In 2006, urethral gonorrhea positivity was 9% (range: 6-12%) in whites, 14% (range: 9-19) in African Americans, and 7% (range: 4-21%) in Hispanics. Rectal gonorrhea positivity was 8% (range: 3-11%) in whites, 10% (range: 2-12%) in African Americans, and 9% (range: 2-11%) in Hispanics. Pharyngeal gonorrhea positivity was 8% (range: 1-15%) in whites, 6% (range: 1-12%) in African Americans, and 7% (range: 1-28%) in Hispanics.

Urethral chlamydia was 5% (range: 3-8%) in whites; 7% (range: 5-13%) in African Americans, and 6% (range: 4-8%) in Hispanics.

Median syphilis seroreactivity was 7% (range: 6-11%) in whites; 15% (range: 8-26%) in African Americans, and 14% (range: 7-26%) in Hispanics.

STDs by HIV Status, STD Clinics, 2006

In 2006, urethral gonorrhea positivity was 14% (range: 12-31%) in HIV-positive MSM and 8% (range: 7-12%) in MSM who were HIV-negative or of unknown HIV status; rectal gonorrhea positivity was 11% (range: 3-18%) in HIV-positive MSM and 6% (range: 2-14%) in MSM who were HIV-negative or of unknown HIV status; pharyngeal gonorrhea positivity was 6% (range: 1-19%) in HIV-positive MSM and 7% (range: 1-14%) in MSM who were HIV-negative or of unknown HIV status.

Median urethral chlamydia positivity was 7% (range: 5-9%) in HIV-positive MSM and 6% (range: 4-8%) in MSM who were HIV-negative or of unknown HIV status.

Median syphilis seroreactivity was 30% (range: 17-44%) in HIV-positive MSM and 7% (range: 5-13%) in MSM who were HIV-negative or of unknown HIV status.

Nationally Notifiable Syphilis Surveillance Data

P&S syphilis increased in the United States between 2002 and 2006, with a 54.1% increase in the number of P&S syphilis cases among men and a 9.1% decrease in the number of cases among women (Tables 26 and 27). In 2006, the rate of reported P&S syphilis among men (5.7 cases per 100,000 males) was 5.7 times greater than the rate among women (1.0 cases per 100,000 females) (Tables 26 and 27). 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 3.4 in 2002 to 5.7 in 2006 (Figure 33, Tables 26 and 27). The increase in the male-to-female rate ratio occurred among all racial and ethnic groups between 2002 and 2006.

In recent years, MSM have accounted for an increasing number of estimated syphilis cases in the United States¹⁵ and in 2006 accounted for 64% of P&S syphilis cases in the United States based on information reported from 29 states and Washington, D.C.¹⁶

Additional information on syphilis can be found in the Syphilis section (National Profile).

Gonococcal Isolate Surveillance Project (GISP)

The 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.^17,18

GISP also reports the percentage of N. gonorrhoeae isolates obtained from MSM. Overall, the proportion of isolates from MSM in GISP clinics increased steadily from 4% in 1988 to 21.5% in 2006 (Figure Z). 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 AA).

---

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 Renault CA, Hall C, Kent CK, Klausner JD. Use of NAATs for STD diagnosis of GC and CT in non-FDA-cleared anatomic specimens. MLO Med Lab Obs 2006; 38(7):10, 12-6, 21-2.

¹³ Jespersen DJ, Flatten KS, Jones MF, Smith TF. Prospective comparison of cell cultures and nucleic acid amplification tests for laboratory diagnosis of Chlamydia trachomatis Infections. J Clin Microbiol 2005; 43(10):5324-6.

¹⁴ Helms DJ, Weinstock HS, et. al. Increases in syphilis among men who have sex with men attending STD clinics, 2000-2005. In: program and abstracts of the 17 Biennial meeting of the ISSTDR, Seattle, WA, July 29-August 1, 2007 [abstract P-608].

¹⁵ Heffelfinger JD, Swint EB, Berman SM, Weinstock HS. Trends in primary and secondary syphilis among men who have sex with men in the United States. Am J Public Health 2007;97:1076-1083

¹⁶ Beltrami JF, Weinstock HS. Primary and secondary syphilis among men who have sex with men in the United States, 2005. In: program and abstracts of the 17 Biennial meeting of the ISSTDR, Seattle, WA, July 29-August 1, 2007 [abstract O-069].

¹⁷ Schwarcz S, Zenilman J, Schnell D, et. al. National Surveillance of Antimicrobial Resistance in Neisseria gonorrhoeae. JAMA 1990; 264(11): 1413-1417.

¹⁸ Centers for Disease Control and Prevention. Sexually Transmitted Disease Surveillance 2006 Supplement: Gonococcal Isolate Surveillance Project (GISP) Annual Report 2006. Atlanta, GA: U.S. Department of Health and Human Services (available first quarter 2008).

---

Page last modified: November 13, 2007
Page last reviewed: November 13, 2007
Content Source: Division of STD Prevention, National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention