Background: Syphilis-HIV co-infection may enhance the infectiousness and severity of both diseases. In New York City, >60% of men-who-have-sex with-men with primary or secondary syphilis are co-infected with HIV. Current criteria for syphilis investigation do not include HIV status. We assessed HIV positivity (HIV+) among persons with reactive serologic tests for syphilis (STS+) to determine if, given current resources, HIV infection alone could be used as a criterion for initiating syphilis investigations.
Methods: We ascertained HIV status for all persons with STS+ reported during December 2012 by providers diagnosing high volumes of syphilis. We first checked HIV status in the STD surveillance registry, which contains limited HIV data. If HIV status was unavailable, we then searched the HIV/AIDS registry (HARS). HARS is supported on an independent network requiring separate login.
Results: Of 675 persons with STS+, 223 (33%) were determined to be HIV+ by checking the STD registry. Of the remaining 452, 24% (163/452) were found to be HIV+ in HARS. Overall, 57% (386/675) persons with STS+ were known to be HIV+ (92% male, median age 41). Among the 11% (74/675) which met existing criteria for syphilis investigation, 69% (51/74) were HIV+ either in the STD or HIV registry.
Conclusions: Checking HARS resulted in a 73% increase in known HIV+ status among persons with STS+. If HIV-infection was the sole criterion for initiating syphilis investigations, an additional 335 persons would have been initiated in one month; given current resources for investigation, this would not be feasible. Instead, we implemented HARS checks for all STS+ persons meeting syphilis investigation criteria who have unknown HIV status. This approach allows field staff to prioritize co-infected persons for investigation. Automated matching of STD and HIV registries would reduce the burden of reviewing two separate surveillance systems, but would not address limited field resources.