High Incidence of Congenital Syphilis in New Zealand A New Zealand Pediatric Surveillance Unit Study

Background: Syphilis, a disease once in decline, has made a resurgence worldwide. New Zealand has had increasing syphilis rates since enhanced syphilis surveillance was initiated in 2013. This study reports epidemiologic, descriptive and treatment data on management of infants prenatally exposed or vertically infected with syphilis across New Zealand as reported by pediatricians. Methods: Over a 26-month period from April 2018 to May 2020 (inclusive), pediatricians throughout New Zealand notified potential, probable and confirmed cases of congenital syphilis to the New Zealand Pediatric Surveillance Unit. National reporting numbers were concurrently ascertained to demonstrate reporting accuracy. Results: Thirty-two cases were notified, comprised of 25 infants born to women with positive antenatal syphilis serology (5 whom developed congenital syphilis), and 7 infants diagnosed with congenital syphilis after birth where syphilis was not diagnosed in pregnancy. There were 12 cases of congenital syphilis; an incidence rate of 9.4 cases per 100,000 live births. Nine of the 12 infants had clinical features of congenital syphilis. One-third of maternal infections were early syphilis, and the women who gave birth to infected infants were less likely to have received antenatal care, adequate treatment and follow-up monitoring of treatment for syphilis during pregnancy. Conclusions: This study quantifies an important burden of disease from congenital syphilis in our population. Case finding and treatment of syphilis in pregnancy are critical to prevent this. Our findings support the urgent need for measures such as repeat maternal syphilis screening in early third trimester; whether by affected region or instituted for all, in the context of rising cases.