Declaration of interest
We would like to acknowledge the support of the National Institute for Health Research Health Protection Research Unit (NIHR HPRU) in Emergency Preparedness and Response at King’s College London in partnership with Public Health England (PHE) as well as the NIHR Biomedical Research Centre at the South London and Maudsley NHS Foundation Trust. Til Wykes and Simon Wessely would also like to acknowledge the support provided by their NIHR Senior Investigator Awards. The views expressed are those of the authors and not necessarily those of the NHS, the NIHR, the Department of Health or Public Health England.