1. Santé Publique France, Saint Maurice, France
2. COVID Vaccines and Epidemiology, UK Health Security Agency, United Kingdom
3. Department of Infectious Diseases, Istituto Superiore di Sanità, Rome, Italy
4. International COVID Team, UK Health Security Agency, United Kingdom
5. National Institute of Public Health Bucharest, Romania
6. University of Medicine “Carol Davila” Bucharest, Romania
7. Department of epidemiology and infectious diseases, Sciensano, Brussels, Belgium
8. Public Health Agency of Sweden, Stockholm, Sweden