(P435) Evaluation of Universal Syphilis Screening at Delivery in British Columbia, Canada

Background: In July 2019, British Columbia (BC), Canada declared a provincial outbreak of syphilis due to increases in congenital and female syphilis rates. In response, all pregnant individuals were recommended a syphilis screen at delivery as of September 2019 to maximize detection and treatment of maternal and congenital syphilis. We assessed the changes in maternal and early congenital syphilis rates following this new recommendation.

Methods: We conducted a quasi-experimental study to compare maternal and congenital syphilis incidence rates reported in BC between the pre-intervention period (July 1, 2018-June 30, 2019) and intervention period (October 1, 2019-September 30, 2022). Crude maternal and early congenital syphilis incidence rate ratios (IRR) using deliveries and prenatal syphilis tests (including testing at delivery) were calculated between these two periods. Prenatal syphilis testing data were identified using a pregnancy flag and extracted from the BC Public Health Laboratory, which performs >99% of all syphilis testing in BC. Delivery data were extracted from the Perinatal Data Registry. Due to reporting delays, deliveries in 2022 were estimated based on the previous year.

Results: During the pre-intervention period, there were 5 maternal and 1 early congenital syphilis cases. In comparison, during the intervention period, there were 71 maternal and 11 early congenital syphilis cases. Comparing the two periods, the IRR of maternal syphilis cases by prenatal syphilis test and by delivery was 3.1 (p=0.005) and 4.8 (p< 0.001), respectively. An increase in early congenital syphilis incidence was observed (IRR=3.7), which was not statistically significant (p=0.19)

During the intervention period, 10% of all syphilis screening at delivery had no evidence of syphilis screening in the current pregnancy. Of the 71 maternal syphilis cases reported in this period, 19 (27%) were identified at delivery, of which 11 (58%) had no evidence of previous prenatal syphilis screening in BC and 8 (42%) had a previous negative screen. Of the 11 early congenital syphilis cases, 5 (45%) were born to mothers who had a previous negative prenatal syphilis screen.

Conclusions: Universal syphilis screening at delivery, in a landscape of increasing syphilis cases, helped identify and allowed prompt treatment of maternal and congenital syphilis cases.