Theory-based Trial to Promote Uptake and Sustained Use of Face Coverings During the COVID-19 Pandemic.

Background: Transmission of airborne viruses can be mitigated by wearing face coverings but evidence suggests that face covering declines with the removal of relevant legislation, partly due to low automatic motivation.

Purpose: Test whether an intervention based on implementation intentions could support people's automatic motivation and promote face covering during the COVID-19 pandemic.

Methods: Randomized controlled design. At baseline (May 20 to June 6, 2022), 7,835 UK adults reported how much time they spent wearing face coverings in work, public transport, and indoor leisure settings as well as their capabilities, opportunities, and motivations. 3,871 participants were randomized to form implementation intentions; 3,964 control participants completed questionnaires only. Measures were repeated 6 months postbaseline (November 1 to November 14, 2022). Data were analyzed using mixed measures ANOVAs and Bayes Factors to examine whether the observed data supported the experimental hypothesis.

Results: The proportion of time spend wearing face coverings declined substantially across the 6-month study period, from 15.28% to 9.87% in work settings, 38.31% to 24.55% on public transport, and 9.58% to 7.85% in leisure settings. Bayes Factors indicated moderate relative evidence of no effect of implementation intentions on behavior in work and leisure settings, and inconclusive evidence of a positive effect on public transport.

Conclusions: In the context of declining COVID-19 rates and removal of legal mandates, implementation intentions were not effective in sustaining face covering. Further research is required to ensure that evidence-based interventions are prepared and deployed in the event of future pandemics.