1. Field Epidemiology Training Programme, Public Health England, London, United Kingdom
2. Centre for Infectious Disease Surveillance and Control, Public Health England, London, United Kingdom
3. European Programme for Intervention Epidemiology Training (EPIET), European Centre for Disease Prevention and Control (ECDC), Stockholm, Sweden
4. Virus Reference Department, Microbiology Services, Public Health England, London, United Kingdom
5. Coach House Surgery, Watford, United Kingdom
6. Public Health England Bristol Public Health Laboratory, Bristol, United Kingdom