Weaker AstraZeneca Covid-19 vaccine against South African tension

The trial, which enrolled nearly 2,000 volunteers with a mean age of 31 years, was too small and its participants were too young to draw broad conclusions about the overall efficacy of the vaccine in protection against the disease caused. by coronavirus, especially when it comes to hospitalizations or death. . However, their findings contribute to concerns that a mutant virus will make existing Covid-19 vaccines less effective and that shots will need to be updated to protect them against new strains of virus.

Johnson & Johnson and Novavax Inc.,

whose vaccines have not yet been authorized in any country, have also found that their shots were less effective in recent human clinical trials in South Africa. But their vaccines were found to be 50% or more effective in preventing mild to moderate cases of Covid-19 and even more potent in protecting recipients of serious diseases and hospitalization of the new strain.

Sunday’s statement 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 trial had 4,400.

Far and wide

Thirty-two counties have reported cases of the coronavirus variant that first emerged in South Africa.

Countries where variant B1.351 has been detected

UK

First case

reported

December 12th

WE

First case

reported on January 27th

South Africa

First case reported on October 8

UK

First case

reported

December 12th

WE

First case

reported on January 27th

South Africa

First case reported on October 8

UK

First case

reported

December 12th

WE

First case

reported on January 27th

South Africa

First case reported on October 8

WE

First case

reported

January 27

South Africa

First case reported on October 8

The University of the Witwatersrand in Johannesburg, which conducted the AstraZeneca trial, said it could not make an assessment of whether the vaccine provided protection against more severe cases of Covid-19 because participants in the relatively young trial were at low risk. of developing severe Covid -19 symptoms.

However, the chief researcher of the South African trials and scientists at Oxford University who developed the vaccine with AstraZeneca said that, based on the results of other vaccine trials, they were optimistic that their feature would provide protection against severe Covid-19.

“This study confirms that pandemic coronavirus will find ways to continue to spread in vaccinated populations, as expected,” said Andrew Pollard, director of the Oxford University Vaccine Group, in a statement. press on the results of the trials. “But, caught up in the promising results of other studies in South Africa, which use a similar viral vector, vaccines can continue to reduce health systems by preventing serious disease.”

An AstraZeneca spokesman said the company believes “our vaccine could protect against serious diseases.”

The South African strain, known as B.1.351, is already responsible for most infections in South Africa and has been blamed for a sharp rise in Covid-19 cases in countries such as Mozambique and Zambia in recent weeks. .

Taking over

The new variant of the coronavirus quickly eliminated other strains from South Africa

Share of coronavirus strains found in South Africa

Researchers in the United States, Canada, Israel and several European and African countries have also detected it in positive samples of coronavirus tests from people with no recent travel history, suggesting it is spreading to the community. In total, it has been identified in 32 countries and virologists say it is likely to be present in others that do not do systematic sequencing of positive samples.

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

South African researchers have said that variant B.1.351 does not appear to cause more deaths or more severe cases of Covid-19.

Ravi Gupta, a professor of clinical microbiology at Cambridge University who did not take part in the South African trial against the AstraZeneca vaccine, said Sunday’s results underscored the need to update the current Covid-19 vaccine culture against the new variants. Still, he said, he hopes AstraZeneca’s shots will still provide some protection against the new strain. “We definitely still need to use vaccines to protect people from serious illness,” he said.

Concern about the South African variant and its impact on vaccine efficacy has focused on a mutation known as E484K. Researchers believe that this mutation makes antibodies more difficult to catch and neutralize the virus.

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

—Jenny Strasburg contributed to this article.

Write to Gabriele Steinhauser to [email protected]

Corrections and amplifications
Volunteers in a South African trial of AstraZeneca’s Covid-19 vaccine had a mean age of 31 years. An earlier version of this article incorrectly stated that they had an average age of 32 years.