LONDON -- Oxford University and AstraZeneca reported Monday that their coronavirus vaccine was safe and 79% effective overall, completely preventing the worst outcomes from the disease, according to data from a long-awaited clinical trial in the United States, Chile and Peru.
The results, announced in a news release, set the stage for U.S. regulators to decide whether to authorize the easily transported $4 shot after the company submits an application in the coming weeks. The two-shot regimen is already being used in many countries, but authorization by the Food and Drug Administration would open up the U.S. market and send a strong signal to the world about the quality of the inoculation.
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The AstraZeneca results are sure to prompt debate within President Joe Biden's administration about how the shot fits into the U.S. vaccine strategy, if it is authorized. The U.S. government last year placed an order for 300 million doses at a cost of $1.2 billion.
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Based on the timeline for other vaccines, emergency clearance appears unlikely before May, when there will be an increased supply of already authorized vaccines from Moderna, Pfizer-BioNTech and Johnson & Johnson.
Having a fourth would provide the United States with insurance against potential manufacturing or supply mishaps involving the three authorized vaccines, as well as additional options for deploying shots domestically and sending some to other countries that need them. Last week, the Biden administration announced that it would send 4 million doses of the vaccine to Mexico and Canada.
"I think it's too early for us to declare that we are in a surplus position. ... But obviously the more we get confidence in our increased supply, the more flexibility that gives us down the road," whether that involves vaccinating adolescents or sharing the vaccines with other countries, said Andy Slavitt, senior White House adviser on covid-19, during a White House news briefing Monday.
It is too soon to know how the AstraZeneca vaccine will fit into the U.S. vaccine portfolio, said Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases.
"The one thing that one can say for sure is that this is good for the world because it's a cheap vaccine. It's got good results," Fauci said. "They will likely be able to produce enough for a lot of different countries."
Ruud Dobber, president of AstraZeneca's BioPharmaceuticals Business Unit, said that the day the vaccine is authorized, the company will be ready to deliver 30 million doses to the United States, with a total of 50 million ready during that first month. While the U.S. government will determine how to use the 300 million doses already ordered, Dobber said he would be "highly surprised" if they are not used to vaccinate Americans.
The Oxford researchers said an independent monitoring board in the United States "reported no safety concerns among the participants receiving at least one dose of the vaccine."
The Data and Safety Monitoring Board combed through data to look for blood-clotting events similar to those that caused the vaccination effort to be suspended last week in many European countries. While the inoculations were restarted after a pause, the reports of clotting undermined confidence in the vaccine in Europe. The independent board found no suggestion that the vaccine carried an increased risk of clotting.
The trials included 32,449 adult participants in all age groups, most of them in the United States. The volunteers received two standard doses of the Oxford-AstraZeneca vaccine or a placebo, at a four-week interval.
The scientists said the data shows that the vaccine is 79% effective against symptomatic covid-19, the disease caused by the coronavirus, and 100% effective against severe illness. There were five cases of severe illness in the trial, all in the group that received a placebo.
The vaccine proved just as effective in people older than 65 as it was in younger recipients. The virus has proved especially lethal to older adults, and earlier trials of the vaccine were criticized for not recruiting enough older people.
"The data look good. The numbers don't lie," said Fauci, who was briefed on the data Sunday.
The results were reported in a pair of brief news releases from the pharmaceutical company and the university scientists, and they have not yet been peer-reviewed or published.
AstraZeneca said that "vaccine efficacy was consistent across ethnicity and age. Notably, in participants aged 65 years and over, vaccine efficacy was 80%."
Because the United States already has ample supply of vaccines from the three other manufacturers, FDA regulators are unlikely to move on the accelerated timeline that they did with other vaccines.
The Pfizer-BioNTech and Moderna vaccines, which require two doses, have shown more than 90% efficacy against symptomatic covid-19. The Pfizer-BioNTech vaccine requires special handling and must be kept at especially cold temperatures in special freezers.
The one-shot Johnson & Johnson efficacy rate is 66% overall and 72% in the United States in preventing moderate to severe cases of covid-19, according to data presented to the FDA.
The Oxford-AstraZeneca vaccine has advantages: It can be stored in an ordinary refrigerator and is relatively cheap. The company has vowed to sell the vaccine at cost during the pandemic.
If the Oxford-AstraZeneca shot is authorized by the FDA for emergency use, then it will offer the United States a bounty of vaccines -- either to administer to people in the United States or provide to countries in need. Some nations have not administered a single dose of vaccine.
Use of the Oxford-AstraZeneca vaccine was paused across Europe last week after the reports of blood clots. The European Medicines Agency, which regulates drugs in the European Union, declared the vaccine safe and effective and said it was not linked with a rise in the overall risk of blood clots. But the agency did not rule out a possible link to rare cases of clotting in the brain, known as cerebral venous sinus thrombosis.
There were no cases of the blood clots identified in the trial after an investigation by an external safety board that consulted with an independent neurologist.
"The results from the U.S. trial of the Oxford-AstraZeneca vaccine give strong evidence that the vaccine is both safe and highly effective," Matt Hancock, the British health secretary, said Monday. "Vaccines are our way out of this, so when you get the call, get the jab."
The vaccine looked more effective in the U.S. trial than in Oxford-AstraZeneca trials in Britain last year, which showed 62% efficacy.
Meanwhile, Rochelle Walensky, director of the Centers for Disease Control and Prevention, said at the White House briefing on Monday that Americans must recommit to wearing masks and taking other covid-19 mitigation measures to avoid a new surge of the virus in the U.S.
Walensky said cases have begun to rise slightly again, while hospital admissions remain stable and deaths continue to decline. Variants, which are in some cases more contagious or more dangerous, continue to spread, she said.
"Taken together, these statistics should serve as a warning sign for the American people," she said. "We must act now, and I am worried that if we don't take the right actions now, we will have another avoidable surge," as is being seen in Europe.
Walensky repeated a warning that states are lifting restrictions too early, and she called on Americans to continue to wear masks, avoid crowds and wait to travel, even if they've been vaccinated. "I'm calling the American people to action, whether vaccinated or not, to recommit to doing the right thing -- take the steps we know work to stop covid-19," she said.
The U.S. is continuing to ramp up vaccinations, recording back-to-back days over the weekend of at least 3 million shots administered. Slavitt said during the briefing that Johnson & Johnson would increase shipments this week of its one-shot vaccine and will come close to hitting its target of providing 20 million doses by the end of March.
DEATHS ON RISE
Additionally, a top World Health Organization expert on the coronavirus pandemic said Monday that the weekly global count of deaths from covid-19 is rising again, a "worrying sign" after about six weeks of declines.
Maria Van Kerkhove, technical lead on covid-19 at the U.N. health agency, said the growth followed a fifth straight week of confirmed cases increasing worldwide. She said the number of reported cases went up in four of the WHO's six regions, though there were significant variations within each region.
"In the last week, cases have increased by 8%," Van Kerkhove told reporters. "In Europe, that is 12% -- and that's driven by several countries."
The increase is due in part to the spread of a variant that first emerged in Britain and is now circulating in many other places, including eastern Europe, she said.
Southeast Asia registered a 49% week-to-week jump in confirmed cases, while the WHO's Western Pacific region reported a 29% rise largely fueled by the Philippines, Van Kerkhove said. The eastern Mediterranean region saw cases rise 8%, while the number of cases reported in the Americas and Africa declined.
"I do want to mention that it had been about six weeks where we were seeing decreases in deaths," said Van Kerkhove. "And in the last week, we've started to see a slight increase in deaths across the world, and this is to be expected if we are to see increasing cases. But this is also a worrying sign."
Information for this article was contributed by William Booth, Carolyn Y. Johnson and Laurie McGinley of The Washington Post; by Rebecca Robbins, Benjamin Mueller and Noah Weiland of The New York Times; by Josh Wingrove of Bloomberg News (TNS); and by staff members of The Associated Press.