Recent Trend in HIV Co-Infection Among Persons Diagnosed with Early Syphilis, Gonorrhea, and Chlamydia in San Francisco, 2007-2011

Background: The epidemiology of HIV and bacterial STDs overlap substantially.  To better understand subpopulations burdened by multiple conditions, we examined the recent trend in persons diagnosed with STD who were co-infected with HIV by matching HIV and STD cases reported to the San Francisco (SF) Department of Public Health.   

Methods: Persons reported with early syphilis, gonorrhea, or chlamydia among SF residents from 2007-2011 were linked to persons diagnosed with HIV through 2011 and reported as of August 13, 2013 using a sequential matching algorithm.  STD cases were considered to be co-infected with HIV if HIV was diagnosed prior to or through one month after STD diagnosis. STD diagnoses within one month of an HIV diagnosis were considered to be concurrent diagnoses.  The proportion of HIV/STD co-infection was determined for each STD including all episodes of that particular STD in a given year.  The analyses by race/ethnicity, transmission risk and age were restricted to males only, since the HIV epidemic in SF is predominately among males.

Results: During 2007-2011, the proportion of persons with known HIV infection increased among early syphilis cases (53% to 62%) and chlamydia cases (12% to 15%), and remains stable among gonorrhea cases (26% to 25%).  No apparent trend was observed for concurrent HIV infection among STD cases.  Across all years, HIV co-infection with a bacterial STD was more common among men who have sex with men (MSM), compared with heterosexual males.  HIV-co-infection for the STDs examined was also higher among white, Latino and older males.

Conclusions: In San Francisco, a large burden of HIV co-infection is observed among MSM, white, Latino, and older males with STDs. These data highlight the need to integrate STD prevention into routine HIV care.