FILE - In this Nov. 30, 2020 file photo, Thabisle khlatshwayo, who received her first shot for a COVID-19 vaccine trial, receives her second AstraZeneca shot at a vaccine trial facility set at Soweto's Chris Sani Baragwanath Hospital outside Johannesburg, South Africa. South Africa suspended on Sunday Feb. 7, 2021 plans to inoculate its front-line health care workers with the AstraZeneca vaccine after a small clinical trial suggested that it isn't effective in preventing mild to moderate illness from the variant dominant in the country. (AP Photo/Jerome Delay, File)

A woman wears a mask to protect against coronavirus as the passes a wall mural depicting a syringe , n Cape Town, South Africa, Thursday, Jan. 21, 2021. South Africa is preparing a hero’s welcome Monday, Feb. 1, 2021 for the delivery of its first COVID-19 vaccines — 1 million doses of the AstraZeneca vaccine produced by the Serum Institute of India. South African President Cyril Ramaphosa will be part of the red-carpet welcome at Johannesburg’s O.R. Tambo International Airport for the shipment of the vaccines, which will be followed up later this month by another 500,000 doses of the vaccine. (AP Photo/Nardus Engelbrecht)

Funeral workers inside a refrigerated container at AVBOB's funeral parlour in Bellville, Cape Town, South Africa, Wednesday, Feb. 10, 2021. South Africa's health minister announced the country will begin administering the unapproved Johnson & Johnson vaccine to its front-line healthcare workers next week. (AP Photo/Nardus Engelbrecht)

Funeral workers place a coffin inside a refrigerated container at AVBOB's funeral parlour in Bellville, Cape Town, South Africa, Wednesday, Feb. 10, 2021. South Africa's health minister announced the country will begin administering the unapproved Johnson & Johnson vaccine to its front-line healthcare workers next week. (AP Photo/Nardus Engelbrecht)

FILE- In this Nov. 30, 2020 file photo, Shabir Madhi, Professor of Vaccinology at the University of Witwatersrand, walks through a COVID-19 vaccine trial facility set at Soweto's Chris Sani Baragwanath Hospital outside Johannesburg. South Africa is scrambling to come up with a new vaccination strategy to combat COVID-19 following its suspension of the rollout of the AstraZeneca vaccine, after a preliminary test showed weak results in protecting the variant dominant in this country. Among the possibilities being considered are giving one dose of AstraZeneca in the hopes it will protect against severe disease and death from the variant. (AP Photo/Jerome Delay, File)

FILE - In this Nov. 30, 2020 file photo, volunteers wait to be checked at a vaccine trial facility set at Soweto's Chris Sani Baragwanath Hospital outside Johannesburg, South Africa. South Africa suspended plans Sunday Feb. 7, 2021 to inoculate its front-line health care workers with the AstraZeneca vaccine after a small clinical trial suggested that it isn't effective in preventing mild to moderate illness from the variant dominant in the country. (AP Photo/Jerome Delay, File)