bSens.SYPH

6.3 million

Global estimates indicate 6.3 million new syphilis cases among people aged 15 to 49 in 2016. In the same year, there were an estimated 661,000 cases of congenital syphilis, 355,000 of them with adverse birth outcomes: fetal loss or stillbirth, neonatal death, prematurity or low birth weight, or clinical signs of syphilis in the infant. ^1,2

9.6 per 1,000

In Brazil, the reported rate of congenital syphilis rose from 1.9 to 9.6 cases per 1,000 live births between 2007 and 2023, with 297,062 cases reported in the period. WHO's target for eliminating mother-to-child transmission is 0.5 cases or fewer per 1,000 live births. ³

4-fold

Treponemal tests usually stay reactive for life, even after treatment. Treatment is followed with nontreponemal test titers (VDRL or RPR), and only a change of at least 4-fold (two dilutions) between results of the same test is considered clinically significant. ^4,5

66.5%

In a meta-analysis of six case-control studies from 1917 to 2000, 66.5% of pregnancies in women with untreated syphilis had an adverse pregnancy or infant outcome. In women without syphilis the figure was 14.3%, and the authors report large heterogeneity between the studies. ⁶

The US Preventive Services Task Force (USPSTF) recommends screening all pregnant people for syphilis early in pregnancy, or at the first available opportunity if that did not happen (grade A recommendation, 2025). It concludes with high certainty that this screening has a substantial net benefit. ⁷

A 2014 Cochrane review found two cluster-randomized trials, at high or unclear risk of bias for most domains, that compared on-site syphilis testing at antenatal clinics with conventional testing. In Mongolia, on-site testing increased testing and treatment and reduced congenital syphilis. In rural South Africa, among women who tested positive, there was no clear evidence of an effect on adequate treatment or perinatal mortality. The authors call for more trials. ⁸