LONDON (AP) – AstraZeneca’s COVID-19 vaccine provided strong protection against disease and complete protection against hospitalization and death in all age groups in an advanced stage study in the United States, the company announced on Monday.
AstraZeneca said its experts have also not identified safety concerns related to the vaccine, including a rare blood clot that has been identified in Europe. The scientists found no increased risk of clots among the more than 20,000 people who took at least one dose of the AstraZeneca injection.
Although the AstraZeneca vaccine has been authorized in more than 50 countries, it has not yet received a green light in the United States. The US study involved more than 30,000 volunteers, two-thirds of whom received the vaccine, while the rest received false injections.
In a statement, AstraZeneca said that its COVID-19 vaccine had a 79% effectiveness rate in preventing symptomatic COVID and was 100% effective in stopping serious illness and hospitalization. The researchers said the vaccine was effective at all ages, including older people – which previous studies in other countries have failed to establish.
“These findings confirm previous observed results,” said Ann Falsey, of the University of Rochester School of Medicine, who helped conduct the study. “It is exciting to see similar efficacy results for the first time in people over 65.”
Julian Tang, a virologist at the University of Leicester who had no connection to the study, described it as “good news” for the AstraZeneca vaccine.
“Previous trials in the UK, Brazil and South Africa had a more variable and inconsistent design and it was thought that the US FDA would never approve the use of the AZ vaccine based on that, but now the US clinical trial has confirmed the effectiveness vaccine in their own clinical trials, ”he said.
The first findings of the study in the USA are just a set of information that AstraZeneca must send to the Food and Drug Administration. An FDA advisory committee will publicly discuss the evidence behind the injections before the agency decides whether to allow emergency use of the vaccine.
Scientists are waiting for the results of the American study in the hope that it will clear up some of the confusion about how well the injections really work.
Britain authorized the vaccine for the first time based on partial test results in the United Kingdom, Brazil and South Africa, which suggested that the vaccines were about 70% effective. But those results were overshadowed by a manufacturing error that led some participants to receive only half a dose on their first dose – a mistake that the researchers did not immediately recognize.
Then came more questions about how well the vaccine protected the elderly and how long to wait before the second dose. Some European countries, including Germany, France and Belgium, initially suspended the injection of older adults and only reversed their decisions after new data suggested that it is offering protection to the elderly.
The development of the AstraZeneca vaccine was also difficult in the USA. Last fall, the Food and Drug Administration suspended the company’s study of 30,000 Americans for an unusual six weeks, while frustrated regulators sought information about some neurological complaints reported in Britain; ultimately, there was no evidence that the vaccine was to blame.
Last week, more than a dozen countries, mainly in Europe, temporarily suspended the use of the AstraZeneca injection after reports that it was linked to blood clots. On Thursday, the European Medicines Agency concluded after an investigation that the vaccine does not increase the overall risk of blood clots, but cannot rule out that it is linked to two very rare types of clots.
France, Germany, Italy and other countries resumed using the vaccine on Friday, with top politicians rolling up their sleeves to show that the vaccine was safe.
AstraZeneca said it will continue to analyze US data in preparation to send it to the FDA in the coming weeks. He said the data would also be published soon in a peer-reviewed newspaper.
The AstraZeneca vaccine is what scientists call a “viral vector” vaccine. Vaccines are made with a harmless virus, a cold virus that normally infects chimpanzees. It acts like a Trojan horse to transport genetic material from the peak protein to the body, which in turn produces a harmless protein. This prepares the immune system to fight if the real virus appears.
Two other companies, Johnson & Johnson and CanSino Biologics from China, make COVID-19 vaccines using the same technology, but using different cold viruses.
AstraZeneca injection has become a key tool in European countries’ efforts to boost their slow vaccine implementations. It is also the pillar of a UN-supported project known as COVAX, which aims to bring COVID-19 vaccines to the poorest countries.
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Neergaard reported from Washington.
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