Why Is Congenital Syphilis Still a Concern in South Africa?
Congenital syphilis (CS) refers to the mother-to-child transmission of syphilis (MTCTs) during pregnancy or childbirth. It occurs when a woman infected with Treponema pallidum—the bacteria that causes syphilis—becomes pregnant or when a pregnant woman acquires the infection during the pregnancy, and the infection remains undetected, untreated, or inadequately treated.
In the absence of treatment, 50–90% of pregnant women with syphilis will transmit the infection to their unborn child, resulting in adverse pregnancy or birth outcomes such as stillbirths, preterm or low birthweight deliveries and associated complications, early neonatal deaths, and congenital infections. Pregnant women living with HIV and co-infected with syphilis are more likely to transmit HIV to their unborn babies compared to pregnant women living with HIV but without syphilis.
Screening and testing pregnant women for syphilis remains the cornerstone of the elimination of the MTCTs plan. This plan, launched by the World Health Organisation in 2007, requires that countries ensure that 95% of pregnant women attend antenatal care, ideally before 20 weeks, that 95% of those who attend antenatal care are screened and tested for syphilis, and that 95% of pregnant women who have syphilis are treated with benzathine penicillin. Countries will be considered to have eliminated congenital syphilis when they have a case rate that is less than 50 cases/100 000 live births in the presence of a robust surveillance system.
South Africa has been screening for antenatal syphilis since the late 1990s and has included congenital syphilis (CS) on the national Notifiable Medical Conditions (NMC) platform since 2017 to monitor progress toward eliminating mother-to-child transmission. Healthcare workers are required to report CS cases within seven days, with additional surveillance through RPR-positive results in children under two. In July 2023, a combined case notification and investigation form (CNF/CIF) was introduced for more efficient case reporting and classification.
This report presents trends in CS notifications and RPR-positive results for 2023.
Materials and Methods
On 26 July 2024, data on notified cases and RPR-positive results from children <2 years of age (CS alerts) for the period 1 January 2023 to 31 December 2023 was extracted. This data was extracted from the NICD’s NMC platform. Following data cleaning and recoding of variables, we used descriptive statistics—counts, frequencies, and percentages—to describe quarterly trends in clinical notifications and laboratory alerts of RPR-positive results at the national, provincial, and district levels. Infants/children who met the criteria for both a clinical case and an RPR-positive result (CS alert) were considered clinical cases. Some children <2 years of age are initially identified as a laboratory alert, following which a notification form providing additional clinical details is completed.
Results
During 2023, there were 1 739 clinical notifications of CS and 5 160 alerts of RPR-positive results from children <2 years of age. The number of clinical notifications was equivalent to a case rate of 198 cases per 100 000 live births. Over this period, there was a steady increase in the number of clinical notifications received. The number of laboratory alerts of RPR-positive results decreased by 30% in the last two quarters of 2023.
At the provincial level during 2023, clinical notifications were highest in the KwaZulu-Natal, Gauteng, Western Cape, and Eastern Cape provinces. These four provinces accounted for 89.9% of all clinical notifications, with KwaZulu-Natal Province alone accounting for 46% of clinical notifications. Clinical notifications increased throughout the year in Mpumalanga Province, albeit from a very low base, i.e., from seven in Quarter 1 to 32 in Quarter 4. The number of CS clinical notifications was equivalent to case rates of 14 per 100 000 live births in Limpopo Province to 418 per 100 000 live births in Western Cape Province.
The numbers of RPR-positive results from children <2 years of age were also highest in the KwaZulu-Natal, Gauteng, Western Cape and Eastern Cape provinces, contributing 81.1% of all RPR-positive results captured in the system.
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