1 Department of Infectious Disease and Tropical Medicine, Heidelberg University Hospital, 69120 Heidelberg, Germany; South African Centre for Epidemiological Modelling and Analysis, Stellenbosch University, Stellenbosch, South Africa. Electronic address: florian.marx@uni-heidelberg.de.
2 Department of Infectious Disease and Tropical Medicine, Heidelberg University Hospital, 69120 Heidelberg, Germany.