Rates of Primary and Secondary Syphilis By State Among Men Who Have Sex with Men - United States, 2014

Background:  In the United States, cases of primary and secondary (P&S) syphilis have increased among men who have sex with men (MSM) with MSM accounting for 61% of all P&S syphilis cases in 2014. Until now, we have been unable to calculate state-specific rates of P&S syphilis among MSM because state-level MSM population estimates were not available.

Methods:  Using 2014 population estimates of the number of adult MSM (≥ 18 years) by state based on a recent modeling study, we calculated rates of P&S syphilis among adult MSM. 2014 P&S syphilis case counts were obtained from national case report data routinely reported to CDC, which includes sex of partner. For states reporting sex of partner for at least 70% of male P&S syphilis cases, we estimated state-specific rates of P&S syphilis among adult MSM and compared them to rates among adult men reporting a female sex partner only.

Results:  Among 40 states reporting sex of partner for at least 70% of male P&S syphilis cases, the overall rate among adult men was 15.0 per 100,000 in 2014. The rate among adult MSM was 271.6 cases per 100,000 (state-specific range: 20.7 to 606.4 per 100,000) and the rate among adult men reporting a female sex partner only was 2.2 per 100,000 (state-specific range: 0 to 6.9). Overall the rate of P&S syphilis among MSM was 124 times the rate among adult men reporting a female sex partner only and ranged across states from 14.9 to 450.4.

Conclusions:  These are the first state-specific rates of P&S syphilis for adult MSM in the US. Rate ratios comparing rates of P&S syphilis among adult MSM to adult men reporting a female sex partner only showed dramatically higher rates among MSM and better illustrates the disproportionate impact of P&S syphilis among MSM in the US.