1. Division of Mathematical Statistics, Stockholm University, Stockholm, Sweden.
2. Department of Epidemiology, Swedish Institute for Infectious Disease Control (SMI), Stockholm, Sweden.
3. Stockholm Group for Epidemic Modeling, Stockholm, Sweden.
4. Department for Biostatistics and Applied Mathematics, University of Texas M.D. Anderson Cancer Center, Texas.
5. Department of Medical Epidemiology and Biostatistics, Karolinska Institute, Stockholm, Sweden.
6. European Centre for Disease Prevention and Control (ECDC), Stockholm, Sweden.