Conclusive data now bear out that among men who have sex with men (MSM), those infected with HIV have a much higher syphilis diagnosis rate than those who are HIV-negative.  This disparity varies widely between states, which could be as a result in part by more frequent testing among MSM living with the virus.  Or, the disparity could be minimized by more sexual contacts between the two groups.

     Recently, Centers for Disease Control and Prevention (CDC) researchers unveiled their findings of the analysis of MSM syphilis diagnosis rates at the 2018 Conference on Retroviruses and Opportunistic Infections (CROI) in Boston.

     According to, “Before conducting this analysis, which provided the first estimate of the ratio of syphilis diagnoses among MSM with HIV versus those without, the CDC researchers already knew that the majority of syphilis diagnoses between 2012 and 2016 were among MSM.  During that period, between 48 percent and 57 percent of annual diagnoses among MSM were seen in those who had HIV.”


The “Skinny” on Syphilis

     Syphilis is a bacterial infection (Treponema pallidum) that is most often spread through sexual contact.  Usually, this infection causes the disease over several years.  In its early stages, syphilis causes disease of the genitals, mucous membranes, and skin.

     And if not treated, the infection can lead to serious problems including heart ailments, neurological issues (neurosyphilis), blindness, dementia—and even death. 

     Since 1996, syphilis rates have been increasing in the U.S.—notably among MSM. 

     Red alert:  if you’re infected with HIV, syphilis can hit you harder.  And faster. 


Delving into The Findings

     The researchers reviewed national case report data on syphilis diagnoses from 2014. For their purposes, that included information on the sex of the individual diagnosed, the sex of that individual’s sex partner, and the men’s HIV status.  They limited their analysis to the 34 states that provided data that classified at least 70 percent of the syphilis cases as women, MSM or men who have sex with women only.

     Among all MSM, the diagnosis rate per 100,000 persons across all 34 states was 237.7, ranging between 35.1 in Montana and 618.3 in Mississippi.

     Overall, those HIV-diagnosed MSM had a syphilis diagnosis rate nearly eight times that of their HIV-negative counterparts.  The statewide diagnosis rate per 100,000 persons among HIV-poz MSM ranged between zero in South Dakota and 2,035 in Arizona.  And among HIV-negative MSM, the statewide diagnosis rate per 100,000 persons in this group ranged between 27 in Montana and 496 in Mississippi.      Therefore, in each state, the ratio of HIV-positive versus HIV-negative syphilis diagnoses varied extensively (excluding South Dakota, the one state with no diagnoses). 

     In conclusion: “The CDC researchers speculate that the disparity in syphilis diagnosis rates may be driven in part by a greater rate of testing for the sexually transmitted infection among those MSM living with HIV compared with HIV-negative MSM,” according to  “Additionally, they conjectured that in states with lower syphilis diagnosis ratios between MSM with and without the virus, more sexual interactions between these two groups might have spread the STI more evenly between them.”