South Africa started to immunize frontline health workers on Wednesday, hours after it received 80,000 doses of the Johnson & Johnson Covid-19 vaccine.

The rollout of the vaccination programme was delayed by two weeks after AstraZeneca's vaccine, which South Africa had initially purchased, was found to be less effective against a new variant that has taken hold in the country.

President Cyril Ramaphosa was among the first to be vaccinated at a hospital near Cape Town on Wednesday afternoon.

"This day represents a real milestone for us as South Africans that finally the vaccines are here and they are being administered," Ramaphosa said after receiving the jab.

South Africa has secured 9 million doses of the one-shot Johnson & Johnson vaccine, which has been proven effective against the currently prevalent 501Y.V2 variant, government said.

The vaccine rollout, initially planned for early February, had to be halted after research showed the AstraZeneca vaccine doses the country had purchased are less effective against the 501Y.V2 variant.

South Africa is the most affected country by Covid-19 on the continent, with almost 1.5 million reported cases and more than 45,000 deaths.