Clinical Stages of Syphilis
Latent syphilis (early and late)
Latent syphilis is the description used when there may be no signs and symptoms, and the infection is detected and classified by a blood test.
While most sexual transmission occurs during primary, secondary syphilis and early latent syphilis, transmission from pregnant person to baby can occur during pregnancy via blood at any stage of syphilis if left untreated. Treatment of latent syphilis differs depending on whether it was acquired within the previous two years (early latent) or more than two years ago (late latent syphilis). If there is no documentation of negative serology in the past two years OR documented treatment in the past two years with a declined in RPR OR no PCR positive result, then treat as late latent syphilis.
If any doubt about the length of infection, treat as late latent syphilis.
|
Stages of latency |
Duration of infection from initial contact |
Treatment |
Infectious? |
|---|---|---|---|
|
Early Latent |
< 2 years |
Treat with benzathine benzylpenicillin injection 2.4 million units (1.8 gm) IM stat |
Yes – Infectious |
|
Late Latent |
> 2 years |
THREE doses total: One dose per week for three weeks* benzathine benzylpenicillin injection 2.4 million units (1.8 gm) IM stat Treatment is very important to prevent long-term consequences. |
No longer infectious to sexual partners but congenital syphilis can still be passed onto the baby during pregnancy. |
*Up to 14 days is an acceptable interval between multiple doses of benzathine penicillin, providing all three injections are given over a period not exceeding 28 days.
Reference: Melbourne Sexual Health Centre. Syphilis treatment guidelines [Internet]. Carlton (VIC): Melbourne Sexual Health Centre; 2021 [cited 17 April 2026]. Available from: https://www.mshc.org.au/health-professionals/treatment-guidelines/syphilis-treatment-guidelines