[1] Univ Witwatersrand, Natl Res Fdn Vaccine Preventable Dis, Dept Sci & Technol, Johannesburg, South Africa
[2] Univ Witwatersrand, Fac Hlth Sci, MRC, Resp & Meningeal Pathogens Res Unit, Johannesburg, South Africa
[3] SUNY Stony Brook, Stony Brook Sch Med, Stony Brook, NY 11794 USA
[4] Emory Univ, Sch Med, Rollins Sch Publ Hlth, Hubert Dept Global Hlth, Atlanta, GA USA
[5] Emory Univ, Sch Med, Div Infect Dis, Atlanta, GA USA
[6] Ctr Vaccines & Immunol, Natl Inst Communicable Dis, Johannesburg, South Africa