LONDON – Britain on Wednesday became the first country to grant emergency authorization for the coronavirus vaccine developed by AstraZeneca and the University of Oxford, paving the way for a cheap and easily storable shot that many of the world will rely on to to help. the pandemic.
In a bold decision to speed up vaccinations, a British government advisory body ordered clinicians to give as many people as possible their first dose of coronavirus vaccine, without discussing stock for the planned second doses.
Instead of administering the two shots within a month, clinicians will wait up to twelve weeks to give people their second doses, a decision that applies to the Oxford-AstraZeneca vaccine as well as the Pfizer-BioNTech vaccine. shot that Britain approved. early this month.
As vaccination is moving slowly in Britain and the United States, British officials have heeded calls for delaying the second dose as a way to partially protect more people from a single dose. Health Secretary Matt Hancock said people would start vaccinating AstraZeneca early next week.
For Britain, where hospitals are overwhelmed by an avalanche of cases of a new, more contagious variant of the virus, the drug regulator’s decision offers some hope of procrastination. The health service is preparing to vaccinate a million people a week on temporary sites in football stadiums and racetracks soon.
The Oxford-AstraZeneca shot is poised to become the world’s dominant form of vaccination. At $ 3 to $ 4 per dose, this is a fraction of the cost of other vaccines. And it can be shipped for six months at normal refrigeration temperatures and not in the ultra-cold freezers needed by competing vaccines from Pfizer-BioNTech and Moderna, making it easier to administer to people in poorer and harder-to-reach parts of the country. world.
When given in two doses at full strength, AstraZeneca’s vaccine has shown 62 percent efficacy in clinical trials – significantly lower than the efficacy of approximately 95 percent achieved by Pfizer and Moderna’s shots. For reasons why scientists do not yet understand it, the AstraZeneca vaccine has shown 90 percent efficacy in a smaller group of volunteers given a starting dose of half strength.
In announcing the authorization on Wednesday, the UK Department of Health did not immediately specify which administration regimen was approved, and whether clinicians would be given space to choose between the two.
In addition to the dosage questions, the UK Health Service must also find out how to persuade people to take a vaccine that seems less effective than other available shots, but which could speed up the end of a pandemic that kills hundreds of people every day in Britain . and thousands more around the world.
The authorization is based on data from late-stage clinical trials in Britain and Brazil. It is also expected that the Drug Regulator of India will soon decide whether to authorize the vaccine, which is manufactured there by a local vaccine manufacturer, the Serum Institute.
A decision is further in the United States, where the Food and Drug Administration is waiting for data from a separate clinical trial. The study was discontinued in September and delayed by almost seven weeks – much longer than in other countries – because regulators are investigating whether a disease in a UK participant is linked to the vaccine. U.S. regulators eventually allowed the trial to continue.
Over the past few days, Oxford scientists who developed the vaccine have been debating on both sides of the Atlantic whether the planned second doses of these and other vaccines should be delayed to give more people the partial protection of a single dose. to give. Andrew Pollard, director of the Oxford Vaccine Group, said in a radio interview on Monday that “it makes a lot of sense to get started with as many people as possible” by postponing the second dose.
AstraZeneca has set more ambitious manufacturing targets than other vaccine manufacturers, saying it expects to be able to make up to three billion doses next year. At two doses per person, it is enough to vaccinate almost one in five people worldwide. The company has undertaken to make it available to the world at least July 2021 at cost, and in poorer countries forever.
But the firm is also plagued by communication flaws that have damaged relationships with U.S. regulators and raised doubts about whether the vaccine will provide an intense public and scientific investigation. These mistakes set the vaccine’s timeline back in the United States, where key FDA officials were stunned to learn from the interruption in its clinical trials in September not from AstraZeneca, but from the news media.
These setbacks have not dampened Britain’s enthusiasm for the country’s leading indigenous vaccine, which analysts say could be corrected in Prime Minister Boris Johnson’s careful tenure if rolled out quickly.
After ordering 100 million doses, of which 40 million would be available in March, Britain launched the AstraZeneca as the core of its vaccination strategy. Since the approval of Pfizer’s vaccine on December 2, Britain has used it to vaccinate hundreds of thousands of people. But the country has struggled to administer it outside hospitals and doctor’s offices, and some of the recipients with the highest priority, such as residents of nursing homes, are still vulnerable.
A small number of volunteers in the clinical trial in Britain received their first dose at half strength due to a measurement problem. Oxford has hired an outside manufacturer to manufacture the vaccine for the trial. But when researchers received a sample of the vaccine, they found that its potency was twice as high as that found by the manufacturer using a different measurement technique. Not knowing what measurement to trust, they decided to halve the dose to ensure volunteers did not get the double dose originally intended. Later, Oxford researchers confirmed that their reading was too high, and they switched back to the originally planned dose for the second survey.
In the smaller group of 2,741 people who received the first half of the first dose or a meningococcal vaccine, the vaccine was found to be 90 percent effective. None of the participants were older than 55, which made it difficult to know whether the results would apply to older people.
Scientists from AstraZeneca and Oxford said they did not know why the half-strength initial dose was so much more effective. But they expressed confidence in their results, especially the finding that no one who received the vaccine in the clinical trials developed serious Covid-19 or was hospitalized.
“We think we’ve determined the winning formula and how to get the effectiveness that is after two doses there with everyone else,” Pascal Soriot, CEO of AstraZeneca, told The Times of London in an interview published on Saturday. The company has not disclosed any evidence of the efficiency rates of Pfizer or Moderna. “I can not tell you anymore, because we will publish at some point,” said Mr. Soriot told The Times.
Scientists from Oxford published interim findings of the clinical trials of the vaccine in The Lancet earlier this month. Future final results of the trials are not expected to differ significantly from the interim data, as is typical in clinical research.
AstraZeneca’s US trial last week enrolled more than 27,000 participants, just under the target of 30,000. The trial could have results and, if positive, lead to an emergency permit in the United States in February or March. Moncef Slaoui, head of Operation Warp Speed, the US federal effort to accelerate coronavirus vaccines, told a news conference. last week.
Managers of AstraZeneca have been pushing various ideas in public for gathering additional data on the more promising dosing regimen. In November, they said they were considering adding an arm to the ongoing U.S. trial or launching a new global trial. But so far none of these proposals have come to fruition.