1 Immunisation and Vaccine-Preventable Diseases Division, UK Health Security Agency, London NW9 5EQ, UK. Electronic address: zahin.amin@phe.gov.uk.
2 Immunisation and Vaccine-Preventable Diseases Division, UK Health Security Agency, London NW9 5EQ, UK.
3 Respiratory and Vaccine Preventable Bacteria Reference Unit, UK Health Security Agency, London NW9 5EQ, UK.
4 Immunisation and Vaccine-Preventable Diseases Division, UK Health Security Agency, London NW9 5EQ, UK; Respiratory and Vaccine Preventable Bacteria Reference Unit, UK Health Security Agency, London NW9 5EQ, UK.
5 Immunisation and Vaccine-Preventable Diseases Division, UK Health Security Agency, London NW9 5EQ, UK; Paediatric Infectious Diseases Research Group (PIDRG), St George's University of London, London, UK.