An online RCT on behavioural expectations effects of COVID-19 certification policies in England

Objective: The aim of this study was to compare the effects of different types of COVID-19 certification policy on subsequent behavioural expectations. Design: 4 × 2 between-subjects pre-registered randomised controlled trial. Method: In August 2022, participants (n = 2726) in England were presented with a scenario describing a rise in COVID-19 infections and the introduction of new protective measures. The protective measures described varied with regards to the setting (healthcare vs. recreational) and the type of policy (no certification vs. vaccination vs. vaccination or free Lateral Flow test vs. vaccination or Lateral Flow test at personal cost). Participants then answered questions on their expectations to receive another dose of the COVID-19 vaccine, to receive the seasonal influenza vaccine and to adhere to other protective behaviours following the announcement, as well as questions based on Self-Determination Theory, COVID-19 vaccine hesitancy and broader vaccine hesitancy. Results: We found no main effects of setting or type of certification on expectation to receive the next dose of the COVID-19 vaccine, to receive the seasonal influenza vaccine, or to adhere to other protective measures, when controlling for baseline expectations. Conclusions: These findings suggest that it is unlikely that the concept of certification, however it is framed, alters inclinations in the English population towards COVID-19 and seasonal flu vaccination or inclinations towards adhering to other protective behaviours within settings to which certification would apply. These findings are based on a hypothetical scenario and should be interpreted with caution.