1. Population Health Sciences, Bristol Medical School, University of Bristol, Canynge Hall, 39 Whatley Road Bristol, UK
2. NIHR Health Protection Research Unit in Evaluation of Interventions, University of Bristol, Oakfield House, Oakfield Grove, Bristol, UK
3. Field Services, National Infection Service, Public Health England South West, 2 Rivergate Bristol, UK
4. Bristol Veterinary School, University of Bristol, Langford House, Langford, Bristol, UK
5. Screening and Immunisation Team, Public Health England South West, 2 Rivergate Bristol, UK
6. NHS England—South (South West), South Plaza, Marlborough Street, Bristol, UK
7. Department of Paediatric Immunology, Bristol Children’s Hospital, Upper Maudlin St, Bristol, UK