Drug giant AstraZeneca reports that its coronavirus (COVID-19) vaccine was 79 percent effective in U.S. clinical trials, raising the possibility that the U.S. could soon deploy a fourth vaccine against the pandemic.
The vaccine, produced in collaboration with scientists at Oxford University, was tested on 32,000 people in the United States. Its efficacy was similar to results conducted in other nations.
The vaccine has been widely used in Europe, but its use was halted earlier this month after reports of some vaccine recipients developing blood clots. After an investigation, European health regulators determined there was no proven link between blood clots and the vaccine.
Following the completion of the U.S. trial, company officials said they would seek emergency use authorization (EUA) from the U.S. Food and Drug Administration (FDA) for use in the U.S. If approved, the AstraZeneca vaccine would be added to the vaccines produced by Moderna, Pfizer and BioNTech, and Johnson & Johnson.
Like the other approved vaccines, the AstraZeneca vaccine was found to be 100 percent effective at preventing severe forms of COVID-19 and death. It was 80 percent effective in preventing illness in people aged 65 and older.
“These findings reconfirm previous results observed in AZD1222 trials across all adult populations but it’s exciting to see similar efficacy results in people over 65 for the first time, said Ann Falsey, a professor at the University of Rochester School of Medicine and co-lead principal investigator for the trial. “This analysis validates the AstraZeneca COVID-19 vaccine as a much-needed additional vaccination option, offering confidence that adults of all ages can benefit from protection against the virus.”
The U.S. trial results have yet to undergo an independent peer review, a critical last step. AstraZeneca said the results of the U.S. trial will be submitted for publication in a peer-reviewed journal.
Like the Pfizer and Moderna vaccines, the AstraZeneca vaccine requires two doses, four weeks apart, to be fully effective. Previous studies have shown that an extended interval between shots could further improve the efficacy.
The vaccine also has some logistical advantages. Like the Johnson & Johnson vaccine, it can be stored, transported, and handled at normal refrigerated conditions of 36-46 degrees Fahrenheit for at least six months and administered without the need for preparation within existing health care settings.