Deployment of AstraZeneca Covid-19 vaccine discontinued in South Africa after study

The study enrolled approximately 2,000 volunteers with a median age of 31 years was too small and the participants were too young, especially with respect to hospitalization and death, the overall vaccine in prevention from diseases caused by the coronavirus. We could not draw a wide range of conclusions about effectiveness. .. However, the discovery has contributed to concerns that mutant viruses are reducing the effectiveness of existing Covid-19 vaccines and need to update shots to protect against new strains of virus.

Of the 39 volunteers in the AstraZeneca trial found to be infected with a new South African variant, 19 were vaccinated and 20 were placedbo, the trial’s principal investigator and dean of medicine. Said Shabir Madhi. University of the Witwatersland in Johannesburg. Dr. Maddy said these numbers mean that the effectiveness of protecting mild and moderate Covid-19 from new variants is about 10%, but the data are too limited to be statistically significant. I added that.

After the results were announced, South African Health Minister Zweli Mkhize said the country would temporarily suspend the planned deployment of the vaccine until more information was available on the effectiveness of the vaccine. The country planned to administer the first shipment of vaccines to health care workers one million times later this month.

Johnson & Johnson

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Novavax Co., Ltd.

That vaccine Not yet licensed in any countryAlso, recent human clinical trials in South Africa have shown that shots are less effective than trials in the United States and the United Kingdom. However, their vaccine was found to be more than 50% effective in preventing mild or moderate cases of Covid. 19 And even more powerful in protecting recipients from serious illness and hospitalization from new strains.

Approximately 6,500 people participated in the Johnson & Johnson trial in South Africa, and 4,400 people participated in the Nova Bucks trial.

The University of the Witwatersrand said in a statement that it was not possible to assess whether the vaccine prevented more severe cases of Covid-19 because younger study participants were at lower risk of becoming seriously ill. ..

Still, Dr. Maddy and a scientist at Oxford University, who developed the vaccine in AstraZeneca, said Results of other vaccine tests, They were optimistic that their shots would provide protection from the harsh Covid-19. AstraZeneca and its partners have promised about 3 billion doses this year. This is enough to vaccinate 1.5 billion people, much more than any other manufacturer. Over 1 billion doses will go to low and middle income countries.

Andrew Pollard, director of the Oxford Vaccine Group at Oxford University, said in a news release of the test results, “This study confirms that we find a way to keep the pandemic coronavirus spreading to vaccinated populations.” It was. “But given promising results from other South African studies using similar viral vectors, vaccines may continue to reduce the burden on the healthcare system by preventing serious illness. “

AstraZeneca spokesman said the company believes that “our vaccine can prevent serious illness.” Like other vaccine makers, AstraZeneca says it is working on updating shots to target new variants of the virus. I hope that the new vaccine will be ready by the fall.

The South African strain known as B.1.351 is responsible for the majority of infections in South Africa and has been accused of a surge in Covid-19 cases in countries such as Mozambique and Zambia in recent weeks.

Researchers in the United States, Canada, Israel, and many countries in Europe and Africa have also detected it in positive coronavirus test samples from people who have not recently traveled, suggesting that it has spread to the community. doing. It has been confirmed in a total of 32 countries, and virologists say it is likely to exist in other countries that do not systematically sequence positive test samples.

Scientists in South Africa and the United Kingdom have found that the B.1.351 strain is a previous version of the virus, based on the fact that the increase in Covid-19 infections in the second wave of South Africa is much faster than in the first biological study. I think it is about 50% more contagious than. Changes in the structure of the virus.

South African researchers state that the B.1.351 mutant does not appear to lead to more deaths or more severe cases of Covid-19.

Rabbi Gupta, a professor of clinical microbiology at the University of Cambridge who was not involved in the AstraZeneca vaccine trial in South Africa, said Sunday’s results emphasized. Need to update current crops of Covid-19 vaccine Against new variants. Still, he said he hopes AstraZeneca’s shots will provide some protection against new strains. “We need to use vaccines to protect people from serious illness,” he said.

Concerns about the effects of South African variants and their vaccines on efficacy are focused on the mutation known as E484K. Researchers believe that this mutation makes it difficult for antibodies to grab and neutralize the virus.

The same mutation has also been found in another variant found in Brazil.British researchers said they discovered the E484K mutation earlier this month In a small number of patients I was infected with another rapidly spreading coronavirus mutant that was causing the infection there.

— Jenny Strasburg contributed to this article.

Correction and amplification
The median age of volunteers in the AstraZeneca Covid-19 vaccine trial in South Africa was 31 years. Earlier versions of this article mistakenly stated that the average age was 32 years.

Write to Gabriele Steinhauser at [email protected]