MedicalResearch.com Interview with:
Alex de Voux, PhD, Epidemiologist
Centers for Disease Control
Division of STD Prevention
MedicalResearch.com: What is the background for this study? What are the main findings?
Response: Reported cases of primary and secondary syphilis have been increasing steadily in the United States since 2001, with men-who-have-sex-with-men (MSM) accounting for 83% of male primary and secondary syphilis cases with information on sex of sex partner in 2014.
However calculating the true disparity of primary and secondary syphilis cases relative to the MSM population size has been difficult because census data does not routinely collect information on sexual orientation or same-sex behavior. Through a recent collaboration with Emory University and CDC, Grey and colleagues developed refined estimates of the population size of MSM by state allowing us to calculate state-specific rates of primary and secondary syphilis for the first time. Looking at data from 44 states that had information on sex of sex partner for at least 70% of their male primary and secondary syphilis cases, the overall rate of syphilis was 309 per 100,000.
The state level data found syphilis rates among gay and bisexual men ranged widely among the 44 states, from 73.1 per 100,000 in Alaska to 748.3 per 100,000 in North Carolina. Some of the highest rates among MSM were in states in the Southeast and the West.
Comparing rates of syphilis among MSM to men reporting sex with women only (MSW), the overall rate for MSM was 107 times the rate for MSW. By state, the rate among MSM was at least 40 times the rate among MSW – and at most, 340 times the rate among MSW.
MedicalResearch.com: What should readers take away from your report?
Response: This is the first time that state-specific rates of primary and secondary syphilis were calculated for MSM in the United States. These syphilis disease rates better illustrate the disproportionate burden of primary and secondary syphilis among MSM by comparing the absolute case counts to appropriate population size estimates. Additionally, these rates show how syphilis impacts gay and bisexual men harder in some parts of the country than other parts. Knowing the infection rate as well as numbers of infections give us a clearer picture of the risk gay and bisexual men face and helps pinpoint the hardest hit areas.
MedicalResearch.com: What recommendations do you have for future research as a result of this study?
Response: Where possible, local and state jurisdictions can take syphilis disease rates into account in addition to the absolute number of cases as this provides a more holistic picture of the epidemic and helps highlight disease disparities. These disease estimates can be updated annually as new census and syphilis case report data become available and can be used to inform disease modeling efforts to evaluate the efficacy of interventions. Sexually active MSM should be screened for syphilis at least annually and every 3 to 6 months if at increased risk.
MedicalResearch.com: Is there anything else you would like to add?
Response: This new analysis builds on existing CDC surveillance data showing alarming recent increases in syphilis infections nationally, particularly among gay and bisexual men. In 2014, there were nearly 20,000 reported syphilis cases overall, a 15.1% increase in just one year. It’s estimated that gay and bisexual men accounted for at least 60 percent of all primary and secondary syphilis cases.