Syphilis is a curable sexually transmitted infection (STI) caused by the bacterium Treponema pallidum. Syphilis is transmitted during oral, vaginal and anal sex, in pregnancy and through unsafe blood transfusions.  Untreated syphilis can last many years and can cause serious health issues.  Maternal syphilis, if untreated, treated too late, or not treated adequately can result in adverse birth outcomes (ABOs)—such as stillbirth, neonatal death, prematurity, low birth weight, or congenital infection—in 50% to 80% of cases.

Many people with syphilis do not notice any symptoms and are unaware of their infection. Syphilis diagnosis is based on the person’s clinical and sexual history, physical examination, laboratory testing and sometimes radiology. Laboratory tests for syphilis include direct detection of T. pallidum through a microscope or indirect methods such as blood tests. Rapid tests are also available and can provide results in minutes, facilitating immediate treatment initiation.

Using condoms consistently and correctly during sex is the best way to prevent syphilis and many other STIs. Syphilis can also spread through contact with other areas of the body not covered by a condom. Pregnant women should be tested for syphilis at the first prenatal care visit and treated right away if the test result is positive. Congenital syphilis can only be prevented by diagnosing and treating the mother with injectable benzathine penicillin. Other activities to reduce new syphilis infections include the screening of asymptomatic individuals for syphilis, and providing partner services to facilitate the testing and treatment of  partners of individuals diagnosed with syphilis.

WHO is working towards eliminating mother-to-child transmission of HIV, syphilis and hepatitis B. As of May 2024, 19 countries and territories had been validated for the elimination of vertical (mother-to-child) transmission of syphilis. The impact and process indicators for a criteria to be validated for the elimination of mother-to-child transmission of syphilis include:

• Congenital syphilis case rate of ≤ 50 per 100 000 live births
• ≥95% ANC coverage (at least one visit) (ANC-1)
• ≥95% coverage of syphilis testing of pregnant women in ANC
• ≥95% adequate treatment of syphilis-seropositive pregnant women