Prevalence and incidence of pharyngeal gonorrhea in a longitudinal sample of men who have sex with men: the EXPLORE study.
BACKGROUND
The prevalence of gonorrhea of the pharynx among select samples of men who have sex with men (MSM) ranges from 9% to 15%. To our knowledge, there have been no longitudinal studies in a prospective MSM cohort to estimate pharyngeal gonorrhea incidence or predictors of infection. We examined the prevalence, incidence, and sociodemographic and behavioral predictors of pharyngeal gonorrhea in a cohort of sexually active, human immunodeficiency virus-negative MSM.


METHODS
We conducted a prospective study of pharyngeal gonorrhea among MSM who were enrolled in a behavioral intervention study to prevent human immunodeficiency virus infection (Project EXPLORE). Participants were enrolled in this ancillary study from March 2001 through July 2003. At baseline and every 6 months thereafter until 31 July 2003, participants were tested for pharyngeal gonorrhea and were administered a questionnaire regarding their oral sex practices. Rectal and urethral gonorrhea testing were also performed.


RESULTS
Prevalence of pharyngeal gonorrhea was 5.5% (136 cases diagnosed from 2475 tests). The incidence rate was 11.2 cases per 100 person-years. Pharyngeal gonorrhea was positively associated with younger age and the number of insertive oral sex partners in the past 3 months. Ejaculation did not increase the risk of pharyngeal gonorrhea. Gonorrhea of the pharynx was asymptomatic in 92% of cases.


CONCLUSIONS
The pharynx is a common, asymptomatic reservoir for gonorrhea in sexually active MSM.
Morris
Sheldon R
SR
Department of Community and Family Medicine, University of California San Francisco, USA.
Klausner
Jeffrey D
JD
Buchbinder
Susan P
SP
Wheeler
Sarah L
SL
Koblin
Beryl
B
Coates
Thomas
T
Chesney
Margaret
M
Colfax
Grant N
GN
D006069:Gonorrhea / Q000453:epidemiology*; D018451:Homosexuality, Male; D006801:Humans; D015994:Incidence; D008297:Male; D009344:Neisseria gonorrhoeae; D010608:Pharyngeal Diseases / Q000453:epidemiology* / Q000382:microbiology; D015995:Prevalence; D011446:Prospective Studies; D012723:Sex; D012725:Sexual Behavior; D012749:Sexually Transmitted Diseases / Q000150:complications / Q000453:epidemiology