1 Institute of Infectious Diseases and Molecular Medicine, University of Cape Town Medical School, Cape Town 7925, South Africa; NRF-DST CAPRISA Centre of Excellence, Cape Town, South Africa; National Health Laboratory Service, Cape Town, South Africa. Electronic address: jo-ann.passmore@uct.ac.za.
2 Institute of Infectious Diseases and Molecular Medicine, University of Cape Town Medical School, Cape Town 7925, South Africa; Seattle Children's Research Institute, Seattle, WA, USA; Department of Global Health, University of Washington, Seattle, WA, USA.