The COVID-19 pandemic's impact on sexually transmitted infections and the modifying role of public health funding: an interrupted time series study.

Background: This study investigated whether the COVID-19 pandemic was associated with changes in sexually transmitted infection (STI) incidence and trajectories in Ontario, Canada and the modifying role of public health funding for infectious and communicable diseases (ICD).

Methods: A repeated cross-sectional study was conducted using population-level age and sex standardized incidence of chlamydia, gonorrhea, and infectious syphilis by public health unit (PHU) in Ontario from January 2015-October 2022. A negative binomial regression interrupted time series analysis estimated trends in STI incidence rates pre- and post-pandemic-onset and whether associations differed by public health ICD funding per capita.

Results: There was an immediate reduction post- compared to pre-pandemic onset in chlamydia (Rate Ratio (RR) = 0.27, 95% confidence interval (CI): 0.21-0.35), gonorrhea (RR = 0.15, 95% CI: 0.02-0.94), and syphilis (RR = 0.16, 95% CI: 0.02-1.18). Post-pandemic onset, a dollar increase in PHU's ICD funding per capita was associated with greater incidence of chlamydia (RR = 1.10, 95% CI: 1.08-1.12), gonorrhea (RR = 1.14, 95% CI: 0.99-1.32) and syphilis (RR = 1.11, 95% CI: 0.97-1.28). Following this initial drop, trends in STI incidence did not differ importantly by ICD funding.

Conclusions: Findings are consistent with a role of public health funding in mitigating observed decreases in STIs. Results suggest that public health funding plays a role in maintaining STI detection services during a public health emergency.