Effect of COVID-19 pandemic restrictions on chlamydia and gonorrhoea notifications and testing in Queensland, Australia: An interrupted time series analysis

Abstract

Objective To investigate trends in testing and notifications of chlamydia and gonorrhoea during the COVID-19 pandemic in Queensland, Australia. Methods Statewide disease notification and testing data between 1 January 2015 and 31 December 2021 were modelled using interrupted time series. A segmented regression model estimated the pre-pandemic trend and observed effect of the COVID-19 pandemic response on weekly chlamydia notifications, monthly gonorrhoea notifications and monthly testing figures. The intervention time point was 29 March 2020, when key COVID-19 public health restrictions were introduced. Results There were 158 064 chlamydia and 33 404 gonorrhoea notifications and 2 107 057 combined chlamydia and gonorrhoea tests across the 72-month study period. All three studied outcomes were increasing prior to the COVID-19 pandemic. Immediate declines were observed for all studied outcomes. Directly after COVID-19 restrictions were introduced, declines were observed for all chlamydia notifications (mean decrease 48.4 notifications/week, 95% CI -77.1 to -19.6), gonorrhoea notifications among males (mean decrease 39.1 notifications/month, 95% CI -73.9 to -4.3) and combined testing (mean decrease 4262 tests/month, 95% CI -6646 to -1877). The immediate decline was more pronounced among males for both conditions. By the end of the study period, only monthly gonorrhoea notifications showed a continuing decline (mean decrease 3.3 notifications/month, p<0.001). Conclusion There is a difference between the immediate and sustained impact of the COVID-19 pandemic on reported chlamydia and gonorrhoea notifications and testing in Queensland, Australia. This prompts considerations for disease surveillance and management in future pandemics. Possible explanations for our findings are an interruption or change to healthcare services during the pandemic, reduced or changed sexual practices or changed disease transmission patterns due to international travel restrictions. As pandemic priorities shift, STIs remain an important public health priority to be addressed.