AstraZeneca Covid-19 vaccine weakens against South Africa tensions

The trial, which enrolled about 2,000 volunteers with an average age of 31 years, was too small and the participants were too young to draw broad conclusions about the overall efficacy of the vaccine to protect the coronavirus from the disease, especially what hospitalizations or death. . However, the findings add to the concern that a mutation virus makes existing Covid-19 vaccines less effective and that shots need to be updated to protect against new virus strains.

Johnson & Johnson and Novavax Inc.,

whose vaccines have yet to be approved in any country have also found that their shots were less effective in recent clinical trials on humans in South Africa. But it has still been found that their vaccinations are 50% or more effective in preventing mild or moderate cases of Covid-19 and even more potent in protecting recipients of serious illnesses and hospitalization from the new strain.

Sunday’s news release on the AstraZeneca trial in South Africa did not provide an efficacy rate for the vaccine. The Johnson & Johnson trial in South Africa included about 6,500 people, while the Novavax one had 4,400 people.

The University of the Witwatersrand in Johannesburg, which conducted the AstraZeneca trial, said they could not assess whether the vaccine provided protection against severe cases of Covid-19, as the relatively young participants in the trial were at low risk. to develop severe Covid. -19 symptoms.

The South African trial researcher and scientists from the University of Oxford who developed the vaccine with AstraZeneca said that, based on the results of other vaccination trials, they are optimistic that their shot will provide protection against serious Covid-19.

“This study confirms that the pandemic coronavirus will find ways to continue to spread in vaccinated populations, as expected,” Andrew Pollard, director of the Oxford Vaccine Group at the University of Oxford, said in a news release on the trial results. “But, taken with the promising results of other studies in South Africa with a similar viral vector, vaccines can still ease the toll on healthcare systems by preventing serious diseases.”

A spokesman for AstraZeneca said the company believed that “our vaccine could protect against serious diseases.”

The South African tribe, known as B.1.351, is already responsible for the majority of infections in South Africa and is blamed for the sharp increase in Covid-19 cases in countries such as Mozambique and Zambia in recent weeks.

Researchers in the US, Canada, Israel and a number of European and African countries have also detected it in positive coronavirus test samples from people without a recent travel history, suggesting that it is spreading in the community. In total, it has been identified in 32 countries, and virologists believe it is likely to be present in others who do not do systematic sequencing of positive test samples.

Scientists in South Africa and the United Kingdom believe that the B.1.351 strain is about 50% more contagious than earlier versions of the virus, based on the much faster increase in Covid-19 infections during South Africa’s second wave in comparison with the first and biological studies of changes to the structure of the virus.

South African researchers have said that the B.1.351 variant does not appear to lead to deaths or serious cases of Covid-19.

Ravi Gupta, a professor of clinical microbiology at the University of Cambridge who was not involved in the South African AstraZeneca vaccine trial, said Sunday’s results highlighted the need to curb the current harvest of Covid-19 vaccines. update new variants. However, he expects the AstraZeneca shots to continue to provide some protection against the new strain. “We should definitely still use the vaccines to protect people from serious diseases,” he said.

Concerns about the South African variant and its impact on the efficacy of the vaccine centered on a mutation known as E484K. Researchers believe that this mutation makes it more difficult to capture antibodies and neutralize the virus.

The same mutation was also found in a separate variant discovered in Brazil. Researchers in the UK said earlier this month that they found the E484K mutation in a small number of patients infected with another rapidly spreading coronavirus variant that causes infections there.

—Jenny Strasburg contributed to this article.

Write to Gabriele Steinhauser by [email protected]

Corrections and reinforcements
The volunteers in a South African trial of AstraZeneca’s Covid-19 vaccine had an average age of 31. In a previous version of this article, it was incorrectly stated that they had an average age of 32.