AstraZeneca says U.S. trial shows COVID-19 vaccine almost 80% effective

The AstraZeneca shot could be the fourth coronavirus vaccine approved for use in the United States, if it receives approval from the FDA. Photo by Luong Thai Linh/EPA-EFE
The AstraZeneca shot could be the fourth coronavirus vaccine approved for use in the United States, if it receives approval from the FDA. Photo by Luong Thai Linh/EPA-EFE

March 22 (UPI) -- Pharmaceutical giant AstraZeneca announced on Monday the results of its long-awaited late-stage U.S. trial of its COVID-19 vaccine, stating it has an efficacy of 79% against symptomatic infection and is 100% effective against severe disease and hospitalization.

The company said it's preparing to apply for emergency use authorization from the Food and Drug Administration. If it receives approval, AstraZeneca's shot would be the fourth coronavirus vaccine approved for use in the United States against COVID-19.


The trial of AstraZeneca's AZD1222 candidate, which was developed jointly with Britain's Oxford University, was conducted in the United States, Chile and Peru with more than 32,000 volunteers who were given two shots at a four-week interval.

Researchers said they saw 141 symptomatic cases.

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"Vaccine efficacy was consistent across ethnicity and age," it said. "Notably, in participants aged 65 years and over, vaccine efficacy was 80%."

Monday's announcement came after the company's vaccine was suspended in a number of countries over concerns about a few cases of blood clotting in recipients of the vaccine. Officials said, however, there has been no definitive link to the vaccine and several European nations resumed administering the shot late last week.


AstraZeneca said Monday that an independent data monitoring board conducted a specific review concerning blood clotting in the late-stage U.S. trial, and found no concerns.

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"These results add to the growing body of evidence that shows this vaccine is well tolerated and highly effective against all severities of COVID-19 and across all age groups," Mene Pangalos, AstraZeneca executive vice president of BioPharmaceuticals Research and Development, said in a statement.

Researchers at Oxford University said the results for the U.S. trial add to the safety data collected in previously testing.

"These results are great news as they show the remarkable efficacy of the vaccine in a new population and are consistent with the results from Oxford-led trials," Oxford investigator Andrew Pollard said in a statement.

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"We can expect strong impact against COVID-19 across all ages and for people of all different backgrounds from widespread use of the vaccine."

More than a dozen countries including Spain, Germany and Italy temporarily suspended the vaccine while the European drug regulator investigated a handful of blood clot cases reported in patients who had been inoculated with the AstraZeneca drug. The countries resumed their vaccine campaigns after the regulator ruled there was no association between the drug and an increased risk in blood clotting.


To date, three coronavirus vaccines have received emergency use authorization in the United States -- formulations from Pfizer, Moderna and Johnson & Johnson. Additional vaccines are also in development at Novavax and Sanofi.

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January 31, 2020
National Institutes of Health official Dr. Anthony Fauci (C) speaks about the coronavirus during a press briefing at the White House in Washington, D.C. Health and Human Services Secretary Alexander Azar (L) announced that the United States is declaring the virus a public health emergency and issued a federal quarantine order of 14 days for 195 Americans. Photo by Leigh Vogel/UPI | License Photo

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