215. Trends in Syphilis and the Impact of the COVID-19 Pandemic in Florida: A multiscale joinpoint regression analysis
Authors: Niu Evan , Sareli Rachel , Eckardt Paula A , Sareli Candice , Niu Jianli 
Published: January 2025

Abstract

Background
Syphilis, a sexually transmitted infection caused by the bacterium Treponema pallidum, has been increasing in incidence both locally and globally. Visualizing and analyzing time series trends of syphilis across different demographics and geographic locations, and how they varied during the COVID-19 pandemic, would help to develop strategies to address the rising syphilis rates.Figure 1.Trends of age-standardized syphilis rates in Florida, 2013 - 2022, stratified by sex, racial and age groups.(A) ASSR by sex; (B) ASSR by racial groups; (C) ASSR by age groups. Ages 10 - 24, 25 - 49, and 50 - 69 years are depicted on the left axis, while ages 0 - 9 and 70+ years are shown on the right y-axis. ASSR, age-standardized syphilis rates.

Methods
Ten years of surveillance data (2013–2022) were extracted from the Florida Department of Health. Average annual percentage changes (AAPC) in age-standardized syphilis rates (ASSR) were analyzed according to age, sex, race, geographic locations, and the COVID-19 pandemic period using joinpoint regression models.Figure 2.Geographic distribution of syphilis cases in Florida, 2013 - 2022.(A) The ASSR at county levels in each year was averaged from 2013 to 2022 and the averaged ASSR in each county is mapped. (B) The AAPC across the entire 10-year period in each county is mapped. ASSR, age-standardized syphilis rates; AAPC, average annual percentage change.

Results
The ASSR significantly increased from 2013 to 2022 across different demographic groups, with an overall AAPC of 11.46 (95% CI 9.85–13.43) (Figure 1). The increase was greater in females, with an AAPC of 20.97 (95% CI, 18.61–24.49), compared to males with an AAPC of 10.34 (95% CI 8.19–12.98). The increasing trend was observed across all age groups, with greater increase among individuals aged 25–49 years (AAPC=12.32, 95% CI 10.09–15.18), aged 50–69 years (AAPC=13.42, 95% CI 9.41–18.89), and aged over 70 years (AAPC=13.63, 95% CI 9.23–21.95), compared to those aged ≤ 24 years (AAPC=7.86, 95% CI 7.06–8.81). The increasing trends were comparable across race groups, with an AAPC of 8.08 (95% CI 5.47–11.15) for Hispanic, 11.84 (95% CI 10.02–14.09) for non-Hispanic White, 10.49 (95% CI 8.75–12.66) for non-Hispanic Black, and 11.29 (95% CI 5.28–19.57) for non-Hispanic other races, respectively. There was an upward trend in ASSR during the COVID-19 pandemic (AAPC=12.99, 95% CI 8.48–16.21) compared to the pre-pandemic period (AAPC=11.58, 95% CI 10.17–12.76), but the difference in AAPC between the two periods did not reach statistical significance. The ASSR and the AAPC varied greatly among counties (Figure 2).

Conclusion
The incidence trend of syphilis increases substantially from 2013 to 2022, with differences observed among age, gender, and geographies in Florida. The COVID-19 pandemic produced an increasing incidence of syphilis. Efforts are needed to implement strategies to address the rising syphilis rates within high-incidence groups and communities across the state.

Disclosures
All Authors: No reported disclosures