Received: 21 August 2018
Accepted: 31 October 2018
First Online: 27 November 2018
Ethics approval and consent to participate
: This study analyses routine surveillance data collected, analysed and published as the legal obligation of PHE under Regulation 3 of the Health Service Regulations 2002. Such analysis does not have separate ethics approval but is covered under existing regulatory frameworks and responsibilities. No extra data requiring separate ethics approval were collected as part of this study. Data from individual patients were pseudo-anonymized before analysis.
: This manuscript does not contain any individual person’s data in any form.
: The authors declare that they have no competing interests.
: Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.