Trends in hepatitis A, B, and shigellosis compared with gonorrhea and syphilis in men who have sex with men in Amsterdam, 1992-2006.

Background: Since the mid-1990s, sexually transmitted infections (STIs) among men who have sex with men (MSM) have increased and appear to be related to more risky sexual behavior. We compare trends in hepatitis A, acute hepatitis B, and shigellosis with the trends of gonorrhea and infectious syphilis in Amsterdam MSM more than a period of 15 years.

Methods: We used data of all reported hepatitis A, acute hepatitis B, and shigellosis, and from all patients newly diagnosed with gonorrhea and infectious syphilis who visited the Public Health Service STI outpatient department in Amsterdam between January 1, 1992 and December 31, 2006.

Results: Hepatitis A incidence remained unchanged in MSM (mean 0.97 per 1000 MSM, range 0.04-2.27), who had 21% of all 1697 infections. Hepatitis B likewise remained unchanged in MSM (mean 0.47 per 1000 MSM, range 0.19-0.77), who had 41% of all 448 infections. Most shigellosis is travel-related (657/974), and 16% of the infections occurred in MSM. Its incidence dropped in general, but not in MSM. Both gonorrhea and infectious syphilis in MSM show a steep increase, mainly after 1998.

Discussion: Hepatitis A, B, and shigellosis do not follow the rising trends of conventional STI in MSM, which are believed to result from increased risky sexual behavior. This disparity in trends implies differences in transmission dynamics. Recent molecular epidemiologic studies suggest that clustered transmission in social MSM networks plays a major role.