Epidemiologic Treatment of Contacts to Infectious Syphilis

Syphilis transmission: a review of the current evidence

“…reported that 9% of seronegative syphilis contacts treated with placebo developed syphilitic lesions or became seropositive over the 3-month observation period. 22 Furthermore, in 1971, Schroeter et al . published an evaluation of prophylactic therapy for syphilis in a placebo-controlled trial.…”

An Update on the Global Epidemiology of Syphilis

“…Syphilis is usually sexually acquired by direct skin-to-skin contact with someone with active primary or secondary lesions. Studies have shown the attack rate of syphilis within 30 days of sexual exposure to someone with syphilis is 16% to 30% [41, 42]. Although commonly thought of as a safer sexual practice, oral sex is an effective route for syphilis transmission [43-45].…”

Public health interventions to control syphilis

“…Studies that followed untreated recent (one month) sex partners of persons with primary or secondary syphilis found 15.9–30.3% developed positive antibody tests. 12,13 Once that high rate of seronegative infection was demonstrated, most clinicians started treating recent contacts presumptively because the risk of undiagnosed infection was so high, the cost of treatment was so low, presumptive treatment removed the need for return visits (or searching for persons who do not return), and it prevented any onward transmission that might otherwise occur while waiting for definitive proof of infection. Treatment of all recently exposed partners of persons with early syphilis is important.…”

“…Lesions are usually painless and often unnoticed, so one-half to three-quarters of infections are diagnosed in the latent stage. 5 Syphilis is transmitted to 15.9%–30.3% of partners of patients with early syphilis (based on the development of antibody during follow-up of untreated sexual contacts from the preceding 30 days); 12, 13 this is slightly less infectious than gonorrhea, where the risk is 19% after one exposure and about 80% after several, 14 and more than HIV which is 0.04%–0.08% per exposure for heterosexual discordant couples. 15 Persons who are cured of syphilis are susceptible to re-infection.…”