18 months on: an interrupted time series analysis investigating the effect of COVID-19 on chlamydia and gonorrhoea testing and test positivity at the Gold Coast, Australia

Abstract

Background: STI rates have been reported as reduced during the height of the COVID-19 pandemic. Our study evaluates the number of Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (NG) infections recorded relative to the number of tests performed in 2017-2021, thus accurately depicting trends over time and evaluate the effect of COVID-19 restrictions since these were implemented in March 2020. Methods: Data was extracted from an electronic database of pathology and clinical records used at Gold Coast Sexual Health Service (GCSHS) in Queensland, Australia from January 2017 to October 2021. Poisson regression-based interrupted time series analyses were performed for number of tests performed and test positivity over the study period. The COVID-19 period was defined as starting from March 2020 when public health directives were implemented. Results: CT and NG testing dropped significantly in the month after COVID-19 restrictions were brought in, by 30% and 23% respectively. Over the 5 year study period, the proportion of positive CT tests has consistently decreased by approximately 0.33% points per year (P ≤ 0.001). The instigation of COVID-19 restrictions had no effect on this trend. The proportion of NG positive tests remained steady prior to COVID-19 (P = 0.96) at approximately 3.5%, decreased immediately at the onset of COVID-19 restrictions to approximately 2.5% (P < 0.001) and has remained at this level post-COVID restrictions (P = 0.54). Testing at GCSHS continued to target gay and bisexual men, accounting for ≥50% of all tests performed. Conclusion: Our study suggests that there has been a sustained reduction in test positivity of NG infections in the 18 months since COVID-19 restrictions were implemented, and that this is not an artifact of reduced testing. It highlights the importance of maintaining health messaging including screening for sexually transmissible infections and maintaining access to services, which may include alternative models of care such as Telehealth, self-testing and collaboration between all sexual health service providers.