Maternal and congenital syphilis in Fiji 2019-2022: a secondary analysis of clinical trial data

Maternal syphilis and congenital syphilis (CS) have been increasing globally, but there are limited data from Fiji. We performed secondary analysis of clinical trial data of intrapartum azithromycin given to pregnant women to determine the prevalence of maternal syphilis and estimate the incidence of probable CS. Healthy, pregnant women at a tertiary hospital were routinely tested for syphilis, and their infants, were enrolled between July 2019 and January 2022. World Health Organisation case definitions for maternal and CS were used. Of the 2112 women enrolled, 2073 (98.2%) were tested for syphilis; 82.7% (n = 1715) were iTaukei (indigenous Fijians), and the median age was 27 years (interquartile range [IQR] 23-32). The maternal syphilis prevalence was 6.6% (n = 137). The majority (85.4%, n = 117) of women with positive serological result received at least one dose of benzathine penicillin 30 days prior to delivery. There were 139 infants born to mothers with positive serological results. The 2.5-year pooled incidence of probable CS was 212 per 100000 livebirths. Confirmation of CS was not possible as results of polymerase chain reaction test of cerebrospinal fluid were not available. Fiji has a substantial burden of maternal and CS. To eliminate mother-to-child transmission, improvements in testing and follow-up are needed, along with comprehensive data and confirmatory testing to accurately determine disease burden.