Temporal trends in test-seeking behaviour during the COVID-19 pandemic

This paper is part of a special issue on Behavioural Epidemiology.Cases identified through mass testing represent only a fraction of infections, depending on the propensity of infected individuals to seek testing. Quantifying the variation in test-seeking behaviour through time or between population subgroups provides important information on testing uptake and supports epidemiological analyses of case data that may otherwise be biased. We quantify trends in COVID-19 test-seeking behaviour in Australia from November 2021 – September 2023 using data from: a weekly nationwide behavioural survey, established by the Australian Government to monitor behavioural responses to COVID-19; and Australia’s FluTracking system, a “participatory surveillance system” for influenza, which was adapted to include COVID-19 relevant questions. We found that peaks in test-seeking behaviour generally aligned with peaks in cases making it likely that the size and peakedness of epidemic waves, as measured by case data, were exaggerated relative to if test-seeking behaviour were constant. We identified differences in test-seeking behaviour by symptoms, jurisdiction and age-group, which changed through time. Our findings demonstrate the dynamism of test-seeking behaviour, highlighting the importance of collecting behavioural data through dedicated surveillance systems.