# Rising congenital syphilis amid declining perinatal HIV: a 7-year study from a tertiary medical center in Oregon

## TL;DR

Congenital syphilis cases are rising in Oregon while HIV cases in newborns are nearly eliminated, highlighting gaps in syphilis screening and treatment.

## Contribution

The study reveals increasing congenital syphilis despite existing protocols and emphasizes the need for improved prenatal screening and targeted testing.

## Key findings

- Pediatric syphilis cases increased from 2 in 2018 to 16 in 2024, all due to maternal transmission.
- HIV positivity declined from 1.0% to 0.5% from 2021 to 2024, with no new pediatric HIV cases identified.
- Syphilis positivity rose from 1.8% in 2018 to 4.3% in 2024, with marked disparities by gender and geography.

## Abstract

We analyzed laboratory testing and positivity trends for syphilis and human immunodeficiency virus (HIV) to evaluate the effectiveness of public health policies and clinical practices. Laboratory data from unique patients were reviewed for syphilis (2018–2024) and HIV (2021–2024), stratified by age, gender, prenatal or newborn status, and county of residence in Oregon. Syphilis testing volumes reflected shifts in healthcare utilization before, during, and after the COVID-19 pandemic. HIV testing increased steadily from 6,627 patients in 2021 to more than 18,600 in 2024. Despite an average of ~10,000 syphilis tests annually, positivity rose from 1.8% in 2018 to 4.3% in 2024, peaking at 5.3% in 2021. In contrast, HIV positivity declined from 1.0% to 0.5% during the same period. Pediatric syphilis also increased—from 2 cases in 2018 to 16 in 2024—all attributed to maternal transmission. No new pediatric HIV cases were identified. Marked gender disparities were evident. Although females were tested at more than twice the rate of males, males were two to five times more likely to test positive for syphilis and two to seven times more likely for HIV. Geographically, cases clustered in densely populated counties with limited healthcare access, reflecting persistent inequities. Syphilis is highly treatable, and congenital cases are largely preventable with timely prenatal screening and treatment. Rising congenital incidence and increasing adult positivity highlight ongoing gaps in screening and prevention. These findings support urgent national action to require universal prenatal syphilis screening and expand risk-based testing for men and underserved populations.

This retrospective study evaluates laboratory-based syphilis and human immunodeficiency virus (HIV) testing outcomes at Oregon Health & Science University from 2018 to 2024, including more than 100,000 patient records. We report a troubling rise in congenital syphilis cases and late-trimester maternal diagnoses, despite existing prenatal screening protocols. In contrast, pediatric HIV was nearly absent, highlighting the impact of universal maternal screening and treatment. Our findings also emphasize persistent disparities by sex, age, and geography and call for a more robust, tiered prenatal syphilis screening policy, along with targeted partner testing. This work is highly relevant to clinicians, public health leaders, and policymakers focused on infectious disease prevention, maternal–child health, and health equity.