In the United States, approximately half of men who have sex with men (MSM) with primary and secondary (P&S) syphilis were also living with HIV.2 In addition, MSM who are HIV-negative and diagnosed with P&S syphilis are more likely to be infected with HIV in the future. 6 Genital sores caused by syphilis make it easier to transmit and acquire HIV infection sexually. There is an estimated 2- to 5-fold increased risk of acquiring HIV if exposed to that infection when syphilis is present. 7 Furthermore, syphilis and certain other STDs might be indicators of ongoing behaviors and exposures that place a person at greater risk for acquiring HIV.