Reaching beyond pregnant women to eliminate mother-to-child transmission of syphilis in Africa

Abstract

Congenital syphilis is a devastating disease that can be prevented by screening and treatment of infected pregnant women. The WHO is leading a global initiative to eliminate mother-to-child-transmission of syphilis with a goal of ≤50 congenital syphilis cases per 100,000 live births and targets of 95% antenatal care, 95% syphilis testing, and 95% treatment coverage. We estimated current congenital syphilis rates for 43 African countries, and additional scenarios in a subset of 9 countries. Our analysis suggested that only 4 of 43 countries are likely to currently have a congenital syphilis rate ≤50 per 100,000 live births, and none of the 9 countries could reach this goal even in 5 different scenarios with improved services. To achieve the eliminate mother-to-child-transmission goal, it appears necessary to intervene beyond services for pregnant women, and decrease prevalence of syphilis in the general population as well.

Keywords::

• Africa
• antenatal care
• congenital syphilis
• maternal syphilis
• mother-to-child transmission
• pregnancy
• Treponema pallidum

Disclaimer

The authors alone are responsible for the views expressed in this article and they do not necessarily represent the views, decisions or policies of the institutions with which they are affiliated.

Financial & competing interests disclosure

The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.

No writing assistance was utilized in the production of this manuscript.

Key issues

• Syphilis can be transmitted during pregnancy and untreated infection can lead to severe adverse pregnancy outcomes in over 50% of cases, including stillbirth, preterm birth, neonatal death or congenital infection in the newborn.

• A global initiative to eliminate congenital syphilis as a public health problem was launched by the WHO in 2007.

• The elimination goal has since been defined as a case rate of congenital syphilis ≤50 cases per 100,000 live births, with process indicator targets of antenatal care coverage (at least one visit) (ANC1) ≥95%, coverage of syphilis testing of pregnant women ≥95%, treatment of syphilis-seropositive pregnant women ≥95%.

• In this modeling exercise, we estimated congenital syphilis rates in African countries given current, elimination of mother-to-child transmission target and ideal conditions using data on ANC1 attendance, syphilis prevalence, and syphilis testing and treatment, using data from global databases and reporting systems.

• This analysis found that estimated congenital syphilis rates were significantly correlated with syphilis prevalence in ANC attendees.

• Only four African countries with low syphilis prevalence (0–0.18%) were estimated to currently have a congenital syphilis rate below the global elimination of mother-to-child transmission of syphilis goal.

• Of the nine countries in Africa with complete data, our model indicated that even if all process goals set by the elimination initiative were met or ideal conditions provided – none of the nine countries would achieve ≤50 congenital syphilis cases per 100,000 live births.

• Because of relatively high current ANC1 coverage in eight of the nine countries, improvement in syphilis testing and treatment services may have a greater impact on reducing congenital syphilis rates than increasing ANC1 coverage.

• Efforts are needed to improve the effectiveness of penicillin, perhaps through encouragement of earlier ANC attendance, same-day testing and treatment with rapid, point-of-care tests, improvement in penicillin quality control or alternative treatment regimens.

• In order to reduce congenital syphilis rates to <50 cases per 100,000 live births, in addition to improving ANC1 coverage, syphilis testing and treatment and the effectiveness of penicillin, increased efforts are needed to improve primary prevention of syphilis in the general population in order to reduce syphilis prevalence among women to <0.35% before they become pregnant.

Notes

1 Elimination is defined as reduction to zero of the incidence of disease or infection in a defined geographical area. However, because measures to prevent mother-to-child transmission (MTCT) of syphilis are high but not 100% effective, currently it is not feasible to reduce MTCT of syphilis to zero. Therefore, the goal of the elimination of mother-to-child transmission initiative is to reduce MTCT of syphilis to a very low level, such that it is no longer a public health problem.