Received: 28 June 2018
Accepted: 9 November 2018
First Online: 11 December 2018
: Rebecca Webster is affiliated to 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), in collaboration with the University of East Anglia and Newcastle University. 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. The funders had no input in the writing of and the decision to submit this article.
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