1 Departments of Family Medicine and Immunology, University of Pretoria, Pretoria 0001, South Africa. Electronic address: theresa.rossouw@up.ac.za.
2 Interdisciplinary Arts and Sciences, University of Washington Bothell, Bothell, WA, USA.
3 Departments of Pediatrics, Laboratory Medicine and Global Health, Divisions of Infectious Diseases and Virology, University of Washington, Seattle, WA, USA.