LONDON (AP) – AstraZeneca’s COVID-19 vaccine provided strong protection against disease and complete protection against hospitalization and death in all age groups in a late US study, the company announced Monday.
AstraZeneca said its experts also did not identify any safety concerns regarding the vaccine, including a rare blood clot identified in Europe. Scientists found no increased risk of blood clots in the more than 20,000 people who received at least one dose of AstraZeneca shot.
Although the AstraZeneca vaccine has been approved in more than 50 countries, it has not yet received the green light in the US. The U.S. study consisted of more than 30,000 volunteers, two-thirds of whom received the vaccine, while the rest received dummy shots.
In a statement, AstraZeneca stated that the COVID-19 vaccine has an efficacy rate of 79% to prevent symptomatic COVID and that it is 100% effective in stopping serious diseases and hospitalization. Investigators said the vaccine is effective at all ages, including older people, which have not been identified in previous studies in other countries.
“These findings confirm previous observed results,” said Ann Falsey of the University of Rochester School of Medicine, who helped lead the trial. “It’s exciting to see similar efficacy results in people over 65 for the first time.”
Julian Tang, a virologist at the University of Leicester who was not involved in the study, described it as ‘good news’ for the AstraZeneca vaccine.
‘Earlier trials in the UK, Brazil and South Africa had a more volatile and inconsistent design and it was thought that the US FDA would never approve the use of the AZ vaccine on this basis, but now the “American clinical trials confirm the effectiveness of this vaccine in their own clinical trials,” he said.
The early findings of the US study are just one set of information that AstraZeneca needs to submit to the Food and Drug Administration. An FDA advisory committee will publicly debate the evidence behind the shots before the agency decides whether to allow the vaccine emergency.
Scientists are awaiting the results of the US study in the hope that it will clear up the confusion about how well the shots work.
Britain first approved the vaccine based on partial test results in the United Kingdom, Brazil and South Africa, which suggested that the shots were about 70% effective. But the results were clouded by a manufacturing error that caused some participants in their first survey to receive only half a dose – a mistake the researchers did not immediately acknowledge.
Then came more questions about how well the vaccine protects older adults and how long it should wait before the second dose. Some European countries, including Germany, France and Belgium, initially withheld the shot from older adults and only reversed their decisions after new data suggested it provided parental protection.
AstraZeneca’s vaccine development was also rocky in the US. Last fall, the Food and Drug Administration suspended the company’s study of 30,000 Americans for an unusual six weeks as frustrated regulators seek information on some neurological complaints reported in Britain; finally, there was no evidence that the vaccine was to blame.
Last week, more than a dozen countries, mostly in Europe, temporarily suspended their use of the AstraZeneca shot after reports that it was related to blood clots. The European Medicines Agency concluded on Thursday after an investigation that the vaccine does not increase the overall risk of blood clots, but could not rule out that it is associated with two very rare types of blood clots.
France, Germany, Italy and other countries then resumed their use of the shot on Friday, with senior politicians rolling up their sleeves to show the vaccine is safe.
AstraZeneca has said it will continue to analyze the US data in preparation for its submission to the FDA in the coming weeks. It is said that the data will soon be published in a peer-reviewed journal.
The AstraZeneca vaccine is what scientists call a ‘viral vector’ vaccine. The shots are made with a harmless virus, a cold virus that usually infects chimpanzees. It works like a Trojan horse to carry the genetic material of the ear protein in the body, which in turn produces harmless proteins. This causes the immune system to fight when the real virus emerges.
Two other companies, Johnson & Johnson and China’s CanSino Biologics, make COVID-19 vaccines with the same technology but use different cold viruses.
The AstraZeneca shot has become an important tool in European countries’ efforts to promote their slow vaccination. It is also a pillar of a UN-backed project known as COVAX, which aims to bring COVID-19 vaccines to poorer countries.
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Neergaard reports from Washington.
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