A volunteer receives a Covid-19 test vaccine injection developed at the University of Oxford in Britain, during a clinical trial at the Chris Hani Baragwanath hospital in Soweto, Johannesburg, South Africa.

A volunteer receives a Covid-19 test vaccine injection developed at the University of Oxford in Britain, during a clinical trial at the Chris Hani Baragwanath hospital in Soweto, Johannesburg, South Africa.

© 2020 Siphiwe Sibeko/AP Photo