1 2Immunisation and Countermeasures Division, Public Health England - National Infection Service, London, UK.
2 1Respiratory and Vaccine Preventable Bacteria Reference Unit, Public Health England - National Infection Service, London, UK.
3 3Department of Pathology and Infectious Diseases, School of Veterinary Medicine, Faculty of Health and Medical Sciences, University of Surrey, Guildford, Surrey, UK.