AstraZeneca reported Monday that its COVID-19 vaccine provided strong protection among adults of all ages in a long-anticipated U.S. study, a finding that could help rebuild public confidence in the shot around the world and move it a step closer to clearance in the U.S.
In the study of 30,000 people, the vaccine was 79% effective at preventing symptomatic cases of COVID-19 — including in older adults. There were no severe illnesses or hospitalizations among vaccinated volunteers, compared with five such cases in participants who received dummy shots — a small number, but consistent with findings from Britain and other countries that the vaccine protects against the worst of the disease.
AstraZeneca also said the study’s independent safety monitors found no serious side effects, including no increased risk of rare blood clots like those identified in Europe, a scare that led numerous countries to briefly suspend vaccinations last week.
“I do hope it puts to bed any doubts about the vaccine efficacy,” Mene Pangalos, AstraZeneca’s biopharmaceuticals research chief, told The Associated Press. “Overall where the vaccine is being used, it’s been shown to be highly effective. So I hope that the U.S. study now will continue to give the vaccine some momentum and get it used even further around the world.”
The company aims to file an application with the Food and Drug Administration in the coming weeks, and the government’s outside advisers will publicly debate the evidence before the agency makes a decision.
Pangalos said the vaccine could win emergency authorization toward the second half of April. If so, the company would deliver 30 million doses immediately and an additional 20 million within the first month.
What that will mean for America’s vaccination plans is unclear. The Biden administration already projects there will be enough doses for all adults by the end of May thanks to increasing supplies from the makers of the three vaccines already in use in the U.S. — Pfizer, Moderna and Johnson & Johnson.
Federal officials said they didn’t want to prejudge the FDA’s review but cast the AstraZeneca findings as a victory both for the U.S. supply and the global fight against the virus.
“There are very many countries in Europe and throughout the world who have already authorized this, so the fact that a United States-run study has confirmed the efficacy and the safety of this vaccine I think is an important contribution to global health in general,” said Dr. Anthony Fauci, the top U.S. infectious disease expert.
The AstraZeneca shot, which has been authorized in more than 70 countries, is a pillar of a U.N.-backed project known as COVAX that aims to get COVID-19 vaccines to poorer countries. It has also become a key tool in European countries’ efforts to boost their sluggish vaccine rollouts. That made doubts about the shots especially worrying.
Even before the blood clot scare, scientists hoped the U.S. study would clear up some confusion about how well the vaccine really works. While previous research suggested it was effective in younger populations, there were questions about how well it protects those over 65, often those most vulnerable to COVID-19.
Also, Britain authorized the vaccine based on partial results from testing in the United Kingdom, Brazil and South Africa that suggested the shots were about 70% effective. But those results were clouded by a manufacturing mistake that led some participants to get just a half dose in their first shot.