This survey study is reported in line with Checklist for Reporting Results of Internet E-surveys guidelines.25 Full details of survey distribution, design, administration and time points are available in the published protocol.24 In brief, the survey was initially distributed during the acceleration phase of the first pandemic wave through research networks, training faculties or Royal College Networks via email or instant messaging groups, coordinated by identified site/region leads. The participation link was not shared on wider social media platforms, to avoid international contamination. At completion of the acceleration phase survey, participants entered personal email addresses for direct approach at peak and deceleration phases with a unique survey link to avoid duplication.

The acceleration, peak and deceleration surveys were developed iteratively by the study team and underpinned by evidence, or by consensus where necessary. Psychometric tools were selected by consensus of the study team, considering validity and utility of a range of standardised measures, balanced against the feasibility of delivery and completion by individuals likely to be working at maximum capacity.

Study data were collected and managed using Research Electronic Data Capture hosted at University Hospitals Bristol and Weston NHS Foundation Trust.26 27 Acceleration, peak and deceleration phases were defined a priori and adapted from the United States Centers for Disease Control ‘Preparedness and Response Frameworks for Influenza Pandemics’.28 For each survey, exact survey distribution dates were decided per protocol by team consensus according to available public health data on number of confirmed cases (acceleration phase; UK: 18 March 2020–26 March 2020, Ireland: 25 March 2020–02 April 2020), nationally available COVID-19 daily death rates (peak phase; UK: 21 April 2020–05 May 2020, Ireland: 28 April 2020–12 May 2020) and at 30 days after distribution of the peak phase survey (deceleration phase; UK: 03 June 2020–17 June 2020, Ireland: 10 June 2020–24 June 2020). Participants provided electronic informed consent for each survey.