LONDON – The UK on Wednesday became the first country to approve the emergency coronavirus vaccine developed by AstraZeneca and Oxford University, opening a path to a cheap and easy-to-store shot that much of the world will rely on to help the pandemic.
For the UK, where hospitals are overwhelmed by cases of a new, contagious variant of the virus, the drug agency’s decision offered hope of redress. Healthcare is preparing to vaccinate almost a million people a week in makeshift locations in soccer stadiums and racetracks.
The Oxford-AstraZeneca shot is expected to be the world’s dominant form of vaccination. At $ 3 to $ 4 per dose, this is a fraction of the cost of some other vaccines. And it can be shipped and stored at normal refrigeration temperatures for six months, rather than in the ultra-cold freezers required by competing vaccines from Pfizer-BioNTech and Moderna, making it easier to give to people in poorer and hard-to-reach parts of the world.
At two full-strength doses, AstraZeneca’s vaccine showed 62 percent effectiveness in clinical trials – significantly less than Pfizer and Moderna’s roughly 95 percent effectiveness. For reasons scientists don’t yet understand, AstraZeneca’s vaccine showed 90 percent effectiveness in a smaller group of volunteers given a starting dose of half strength.
Dosage issues aside, the UK healthcare sector also needs to figure out how to convince people to take a vaccine that appears to be less effective than other vaccines available, but which could hasten the end of a pandemic that affects hundreds of people every day are being killed in the UK and thousands more around the world.
The approval was based on data from late-stage clinical trials in the UK and Brazil. The Indian Medicines Agency is also expected to soon decide whether to approve the vaccine, which is made there by a local vaccine manufacturer, the Serum Institute.
In the US, where the Food and Drug Administration is waiting for data from a separate clinical trial, a decision is further away. The study was canceled in September and delayed by nearly seven weeks – much longer than other countries – when regulators looked at whether a vaccine-related disease in a participant in the UK was carried out. The American regulators ultimately allowed the process.
Over the past few days, the Oxford scientists who developed the vaccine have been debating on both sides of the Atlantic whether to delay the planned second doses of this and other vaccines to allow more people to receive partial protection from a single dose. Andrew Pollard, the director of the Oxford Vaccine Group, said in a radio interview Monday that “it makes a lot of sense to start with as many people as possible” by delaying the second dose.
AstraZeneca has more ambitious manufacturing goals than other vaccine manufacturers and expects to manufacture up to three billion doses over the next year. With two doses per person, this would be enough to vaccinate almost one in five people worldwide. The company has committed to offering it worldwide at cost until at least July 2021 and in poorer countries on a permanent basis.
Updated
Dec. 30, 2020 at 12:44 am ET
However, the company has also been haunted by communication errors that have damaged its relationship with American regulators and cast doubts as to whether the vaccine will withstand intense public and scientific scrutiny. These mistakes have shifted the vaccine timeline in the US, where key FDA officials were baffled to learn about the September break in their clinical trials from the news media, not from AstraZeneca.
These setbacks have not dampened the UK craze for the country’s leading homegrown vaccine. According to analysts, this could improve Prime Minister Boris Johnson’s tenure if rolled out quickly.
The UK has made AstraZeneca the linchpin of its vaccination strategy by ordering 100 million doses, 40 million of which should be available by March. The UK has vaccinated hundreds of thousands of people since the Pfizer vaccine was approved on December 2nd. However, the country has struggled to manage it beyond hospitals and doctor’s offices, and some of its highest priority recipients, like nursing home residents, are still at risk.
A small number of volunteers in the UK clinical trial received their first dose at half strength due to a measurement problem. Oxford had hired an outside manufacturer to manufacture the vaccine for the trial. When the researchers received a sample of the vaccine, they found that its strength was twice what the manufacturer had found using a different measuring technique. Unsure of which measurement to trust, the researchers decided to cut the dose in half to make sure the volunteers didn’t get double the intended dose. The Oxford researchers later confirmed their reading was too high and switched back to the originally planned dose for the second shot.
In the smaller group of 2,741 people who received the first half-strength dose or a meningococcal vaccine as a control, the vaccine was found to be 90 percent effective. However, none of these participants were over 55 years of age, making it difficult to know if these results would apply to the elderly.
Scientists at AstraZeneca and Oxford said they didn’t know why the half-strength starting dose was so much more effective. However, they have expressed confidence in their results, particularly in finding that no one who received the vaccine in the clinical trials has developed severe Covid-19 or has been hospitalized.
“We think we’ve figured out the formula for success and figured out how to get the effectiveness that everyone else has after two doses,” Pascal Soriot, managing director of AstraZeneca, told the Times of London in an interview published on Saturday. The company has not released any evidence of efficacy rates as high as Pfizer or Moderna. “That’s all I can tell you because we will be out at some point,” Soriot told the Times.
Oxford scientists published interim results from their clinical studies in The Lancet earlier this month. The upcoming final results of these studies are not expected to differ significantly from the interim data, as is typical in clinical research.
AstraZeneca’s US study had more than 27,000 enrolled participants last week, which was just below the target of 30,000. The study could have results and, if positive, lead to an emergency clearance in the US in February or March, Moncef Slaoui, head of Operation Warp Speed, the US federal effort to expedite coronavirus vaccines, said in a news conference last week.
AstraZeneca executives have publicly released several ideas to collect additional data on the more promising dosing regimen. In November they said they would consider adding an arm to the ongoing US process or starting a new global process. So far, however, none of these proposals have been implemented.
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