1. Julius Global Health, Julius Center for Health Sciences and Primary Care; University Medical Center Utrecht; Utrecht The Netherlands
2. Center for Infectious Diseases Research, Diagnostics and Screening (IDS); National Institute for Public Health and the Environment (RIVM); Bilthoven The Netherlands
3. Center for Health Protection; National Institute for Public Health and the Environment (RIVM); Bilthoven The Netherlands
4. Division of Epidemiology and Biostatistics, School of Public Health, Faculty of Health Sciences; University of the Witwatersrand; Johannesburg South Africa