Why 'one size fits all' is not enough when designing COVID-19 immunity certificates for domestic use: a UK-wide cross-sectional online survey.

Objectives: The present study explored public's willingness to use COVID-19 immunity certificates across six different domestic scenarios.

Design: Cross-sectional online survey.

Setting: UK representative survey conducted on 3 August 2021.

Participants: 534 UK residents over 18 years old.

Interventions: Participants replied to the same set of questions.

Primary And Secondary Outcome Measures: The primary outcome measure was immunity certificates across three different domestic settings: (1) visiting the general practitioner (GP) for a non-urgent health issue; (2) dining in a restaurant and (3) attending a performance in a theatre. For each setting two options, one prioritising (option A) and the other (option B), were offered. Our secondary outcome measures were computed indices from items adapted from the Health Belief Model; attitudes towards sharing immunity status with service providers; prior to COVID-19 lifestyle. In addition, we recorded data about respondents' sociodemographic characteristics.

Results: Respondents were more willing to use immunity certificates that prioritised , rather than when visiting their GP . However, privacy was more favourable in the other two settings (dining in a restaurant (84%) and going to a theatre (83%)) compared with (38% and 39% respectively). Personal beliefs about COVID-19 and immunity certificates were associated with variations in willingness to use these across all scenarios. No variations were observed across sociodemographics and lifestyle.

Conclusions: The findings of this survey suggest that there is not solution for designing immunity certificates. Immunity certificates are complex sociotechnical systems, any attempt to implement these for domestic use should be tailored to different settings and user needs. The design of certification services requires a more evidence-based approach and further research is needed to understand how different settings, design elements (like or ) and personal beliefs about the pandemic should inform their design.