Public Health England Colindale, Public Health England Colindale, Public Health England Colindale, Public Health England Colindale, Public Health England Colindale, Public Health England Colindale, Public Health England Colindale, Public Health England - Immunisation and Countermeasures Division, Public Health England Colindale, Public Health England Colindale, Public Health England Colindale, Public Health England Colindale, Public Health England Colindale, Public Health England Colindale, affiliation not provided to SSRN, Public Health England Colindale, Public Health England Colindale, Public Health England - Immunisation, Hepatitis, and Blood Safety Department, Public Health England Colindale and University of Oxford - NIHR Health Protection Research Unit in Healthcare Associated Infection and Antimicrobial Resistance