1. Division of Epidemiology and Biostatistics, School of Public Health, University of the Witwatersrand , Johannesburg , South Africa
2. Department of Interventions and Clinical Trials, Ifakara Health Institute , Ifakara , Tanzania
3. Department of Infectious Diseases, Bern University Hospital , Bern , Switzerland
4. Department of Medicine, Swiss Tropical and Public Health Institute , Basel , Switzerland
5. University of Basel , Basel , Switzerland
6. Department of Family Medicine and Primary Care, University of the Witwatersrand , Johannesburg , South Africa
7. Division of Infectious Diseases and Hospital Epidemiology, University Hospital Basel , Basel , Switzerland