Have vaginal, anal, or oral sex without a barrier with someone who has syphilis
Have direct skin-to-skin contact with a syphilis sore, rash, or infectious lesion
Share sex toys that are not cleaned or covered between partners
Have sex with multiple partners, especially if partners’ STI status is unknown
Have sex with a partner who has had recent unprotected sex with others
Have sex while either partner has untreated syphilis
Have a baby if the pregnant parent has untreated syphilis during pregnancy
Be exposed to infected blood through rare blood contact situations
Have close contact with infectious sores during sexual activity, even if penetration does not occur