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).
Centers for Disease Control and Prevention
1600 Clifton Rd, Atlanta, GA 30333, U.S.A
Tel: (404) 639-3311 / Public Inquiries: (404) 639-3534 / (800) 311-3435 Department of Health
and Human Services
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