Primary prevention

Protected sexual intercourse using condoms reduces the transmission of acquired syphilis.[26] However, oro-genital sex is an important route of transmission and can occur despite the use of condoms.[16][17] There is no significant evidence to suggest that male circumcision reduces the incidence of syphilis.[27] National screening programmes are in place prior to blood donation and as part of antenatal care during pregnancy. Antenatal screening aims to identify and treat asymptomatic women, thus preventing transplacental transmission.[25]

One open-label randomised trial found that post-exposure prophylaxis with a single dose of doxycycline in high-risk men who have sex with men reduced the risk of syphilis compared with no post-exposure prophylaxis at 10-month follow-up (hazard ratio: 0.27; 95% CI: 0.07 to 0.98; p = 0.047).[28]

Secondary prevention

All patients with syphilis should be screened for chlamydia, gonorrhoea, and blood-borne viruses, such as hepatitis B and C. All patients with syphilis should be tested for HIV.[5]  Syphilis is an important facilitator of HIV transmission. All patients with syphilis should be offered hepatitis B vaccination. Sexual contacts of patients with confirmed syphilis should be screened and offered presumptive treatment if follow-up may be problematic.[5] Antibiotics are the only treatment available for syphilis infection.

Strengthening STI services may have an important role in controlling STIs.[109]

Preventive treatment when there has been sexual contact with an infected person:[5]

  • People exposed within 90 days preceding diagnosis of primary, secondary, or early latent syphilis in a sexual partner should be treated presumptively, on the basis that they may be infected even if seronegative. It is estimated that 30% to 60% of sexual partners of people with early syphilis will develop the infection.[18][19]

  • People exposed more than 90 days before diagnosis of primary, secondary, or early latent syphilis in a sexual partner should be treated presumptively if syphilis serology is not available immediately and if follow-up may be problematic.

  • Treatment of long-term sexual partners of patients with latent syphilis is dependent on clinical evaluation and serology results.

At-risk time intervals:[5]

  • For primary syphilis: exposure 3 months before treatment, plus duration of symptoms.

  • For secondary syphilis: 6 months plus duration of symptoms.

  • For early latent syphilis: 1 year.

The identification and treatment of syphilis should be used as an opportunity to promote safe-sex awareness, encourage condom use, and highlight health impacts associated with high risk behaviour, such as illicit drug use. Conditional cash incentives to encourage safe sexual practices have demonstrated potential in rural Tanzania.[110]

In cases of sexual assault, UK guidelines recommend that prophylaxis should be considered if the perpetrator is known to have infectious syphilis.[54]

In the US, syphilis is a nationally notifiable disease, per the US Centers for Disease Control and Prevention. Providers should contact their local state health department for details.

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