A study, which has not yet been peer reviewed, said the AstraZeneca vaccine provided "minimal" protection against the so-called South African variant.
South Africa has halted the rollout of the AstraZeneca vaccine in the country over concerns it will not be effective against a variant of Covid-19.
Distribution of the AstraZeneca vaccine was due to begin in South Africa this month but has since been put on hold until further study is done on its efficacy against the so-called South African variant.
Zweli Mkhize, South Africa’s health minister, said on Sunday it would be on hold "until the scientists give us clear indications as to what we need to do".
“It’s a temporary issue that we have to hold on AstraZeneca until we figure out these issues,” he said.
Data in a recent study said the vaccine provided minimal protection against the mild-to-moderate infection which is caused by the country's dominant Covid-19 variant.
The study, which was conducted by the University of the Witwatersrand in Johannesburg and is not yet peer reviewed, said the Oxford/AstraZeneca vaccine provided "limited protection against moderate forms" of the virus caused by the South African variant.
Prior to the emergence of this more contagious variant, the AstraZeneca vaccine was showing efficacy of around 75%, researchers said.
AstraZeneca said last weekend it believed the vaccine could protect against severe disease from the variant and added it had already begun adapting its vaccine against the new variant.
On Monday, the
HSE confirmed Ireland will slow down its vaccine rollout this week, with less doses administered than originally planned.
29,000 vaccinations are planned to be given this week, 17,000 less than last week's figure.
