JOHANNESBURG (Reuters) – South Africa will suspend the use of AstraZeneca’s COVID-19 trait in its vaccination program, after data shows it provided minimal protection against mild to moderate infection caused by the dominant variant of the country’s coronavirus.
Health Minister Zweli Mkhize said on Sunday that the government would wait for the advice of scientists on the best way to proceed, after a trial showed that the AstraZeneca vaccine did not significantly reduce the risk of mild to moderate COVID-19 from the 501Y.V2 variant second wave of infections from late last year.
Prior to widespread circulation of the most contagious variant, the vaccine showed an efficacy of about 75%, the researchers said.
In a subsequent analysis based primarily on infections by the new variant, there was only a 22% lower risk of developing mild to moderate COVID-19 compared with those receiving a placebo. Although the researchers said the figure was not statistically significant, due to the design of the trials, it is well below the benchmark of at least 50% that regulators have set for vaccines to be considered effective against the virus. .
The study did not assess whether the vaccine helped prevent severe COVID-19, as it involved mostly relatively young adults who were not considered at high risk for serious illness.
AstraZeneca said Saturday that it believed its vaccine could protect against serious disease and that it had already begun adapting it to the 501Y.V2 variant.
However, Professor Shabir Madhi, principal investigator of the AstraZeneca trial in South Africa, said the vaccine data was a reality check and that it was time to “recalibrate our expectations about COVID-19 vaccines.” .
South Africa expects to vaccinate 40 million people, or two-thirds of the population, to achieve a certain level of immunity to the herd, but has not yet administered a single shot.
He had wanted to launch the AstraZeneca vaccine to health workers shortly after they received a million doses produced by the Serum Institute of India (SII) on Monday.
Instead, it will offer vaccines to health workers developed by Johnson & Johnson and Pfizer / BioNTech in the coming weeks.
“What does this mean for our vaccination program, which we said will begin in February? The answer is that it will continue,” Mkhize told an online briefing. “Starting next week for the next four weeks we hope there will be J&J vaccines, there will be Pfizer vaccines.”
NEW APPROACH
Professor Salim Abdool Karim, an epidemiologist advising the government, said a new approach to vaccinations was needed, given the uncertainty about the effectiveness of current vaccines against the 501Y.V2 variant.
First a vaccine should be used in a specific group to assess hospitalization rates, and then, if it is shown to be effective in reducing hospitalizations, it could be presented in a large-scale deployment, he said.
If it was not effective in reducing hospitalizations, another effective vaccine should be offered to people who had received it, either a variant-based booster or another vaccine, Abdool Karim added.
South Africa is likely to experience a third wave of infections when winter begins in about four months, Madhi said.
He added that it would be “a little reckless” to rule out the million doses of AstraZeneca the country had received when there was still a chance of protecting itself against severe COVID-19.
Anban Pillay, deputy director general of the health ministry, said the expiration date for AstraZeneca doses was in April, but the government was talking to the SII to request an extension or exchange.
Madhi said South Africa may want to rethink its target group for vaccination. “It really has to focus on preventing serious illness and death so it’s likely to be a resurgence soon.”
Reports by Alexander Winning and Olivia Kumwenda-Mtambo; Edited by Alexander Smith and Bill Berkrot