LONDON – The UK on Wednesday became the first country to approve the emergency coronavirus vaccine developed by AstraZeneca and Oxford University, clearing the way for a cheap and easy-to-store shot that much of the world will rely on to help the pandemic.
In a departure from global strategies, the UK government also decided to give as many people as possible a first dose of vaccine instead of holding back supplies for quick second shots, which significantly increases the number of people vaccinated.
That decision put Britain at the forefront of a far-reaching and unsafe experiment to speed up vaccination that some scientists say could alleviate suffering from a pandemic that has killed hundreds of people in the UK and thousands around the world every day.
Global efforts to speed up vaccinations, which are coming as a new, more contagious variant of the virus, are spreading and gained momentum in many places on Wednesday.
China said clinical trial results showed high efficacy for one of its vaccine candidates. This announcement accelerated the global roll-out of hundreds of millions of doses of Chinese vaccines, but contained few key details. Russia’s Sputnik-V vaccine, long criticized for its premature introduction, was also used this week in Argentina, Belarus, Hungary and Serbia, the first other countries to inject it en masse. And Argentina quickly followed Britain in approving the Oxford-AstraZeneca shot, and India should soon too.
The two UK measures on Wednesday – approving an easy-to-make, easy-to-deliver vaccine and delaying second doses of vaccine – offered a plan on how vaccination campaigns, previously embroiled in logistical and manufacturing problems, can be stepped up across much of the west.
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 in regular refrigerators for six months rather than the ultra-cold freezers required for Pfizer-BioNTech and Moderna vaccines. This makes it easier to administer in poor and hard-to-reach areas.
Delaying the second vaccine doses could also double the number of people eligible to be shot in the coming weeks, and ultimately reduce the number of viruses not only in the UK but also in countries with years of vaccine shortages, some scientists said. While a person might be better off with the full two doses, society as a whole would benefit if more people were given partial protection from a single dose for the time being.
“We’re talking about a potential billions in vaccination in any given year versus the alternative of taking two doses and leaving them in a freezer,” said Michael Mina, an epidemiologist at Harvard who was one of their earliest proponents Delay the second dose. “There can be a compromise for any of these people, but at the population level, you can save many more lives.”
However, other scientists believe the UK has exceeded the evidence available, possibly leaving the elderly and healthcare workers in horrific winter floods without the full protection of two doses of vaccine. Britain avoided the public meetings or extensive briefings that preceded American regulatory decisions. The long-term effectiveness of a single shot was not explicitly tested in any study.
And what limited evidence is there of the protection offered by a single dose, which clashes with scientists’ fears that antibody responses may wane over time and potentially fall below a protective threshold.
“What is the longevity of protective immunity for one dose versus two doses?” said John Moore, professor of microbiology and immunology at Weill Cornell Medical College. “Where is the data?”
Britain will delay the second booster dose of not only the Oxford-AstraZeneca vaccine but the Pfizer BioNTech shot as well. In clinical studies, this vaccine, which has been used in the country for several weeks, has been shown to be significantly effective after a single dose. However, Pfizer warned Wednesday that data on the effectiveness of a single dose does not go beyond when people receive their second shots three weeks after the first. The company said two doses “are required to provide maximum protection against the disease”.
For the UK, where hospitals are being overwhelmed by a spate of cases of a new and contagious variant of coronavirus, the introduction of more vaccines offered a distant hope for redress. As of Monday, the health service is preparing to vaccinate up to two million people per week at makeshift locations in football stadiums and on racetracks. However, the first shipment will only contain 530,000 cans.
Apr. 30, 2020, 5:15 pm ET
Instead of giving the two vaccine shots within a month as originally planned, clinicians in the UK will wait up to 12 weeks to give people a second dose, the government said. Doctors tried Wednesday to push back hundreds of appointments for the second dose of the Pfizer BioNTech vaccine and fill it with first-time recipients.
In clinical trials with the Oxford AstraZeneca vaccine, participants were exposed to a delayed second dose. Most of the participants in the UK study received the two doses at least nine weeks apart. UK regulators said Wednesday that the first dose had a 73 percent effectiveness in protecting against Covid-19 in the time between this shot became effective and a second shot was administered. However, scientists cautioned that these numbers apply to a subset of study participants and have limited immunological justification.
Scientists have also raised concerns that the Oxford-AstraZeneca group does not have enough data on the elderly to fully assess the effectiveness of the vaccine in this group. Andrew Pollard, the director of Oxford Vaccine Group, said in an interview on Wednesday that more evidence of the elderly was emerging from an ongoing American trial in which nearly all 30,000 volunteers have participated.
The United States and the European Union have indicated that they are unlikely to approve the Oxford-AstraZeneca vaccine until at least February.
When given in two full strength doses, the UK approved regimen, AstraZeneca’s vaccine has shown 62 percent effectiveness in clinical trials – significantly less than Pfizer and Moderna’s roughly 95 percent effectiveness. Nobody who received the vaccine in the clinical trials developed severe Covid-19 or was hospitalized.
British regulators said the vaccine’s effectiveness appeared to increase to 80 percent in a smaller group of volunteers who were given the two doses for about three months instead of a single month. This finding was not made public, but encouraged regulators to approve a longer gap between doses.
Professor Pollard said the longer interval produced higher levels of antibodies in the participants. And that finding, he said, might help solve a mystery hanging over the Oxford-AstraZeneca group: Why did the vaccine have 90 percent effectiveness in volunteers given a starting dose of half strength instead of full strength. These volunteers happened to have taken their two doses further apart, making it likely that the greater effectiveness was due to the extended gap between doses, rather than the size of the starting dose as originally thought.
Menelas Pangalos, the manager responsible for much of AstraZeneca’s research and development, said in an interview on Wednesday that the company will now work to refine the interval between doses and focus on a possible “sweet spot” of 8 to 12 weeks to focus. However, scientists said such efforts required significantly more data.
And analysts warned that the UK healthcare system could potentially struggle to convince people to take a vaccine that appears to be less effective than other available vaccines, but which could hasten the end of the pandemic.
Much of the world relies on AstraZeneca in part because it has more ambitious manufacturing goals than other western vaccine manufacturers. It is expected that up to three billion doses will be administered over the next year – an amount that, given two doses per person, would be enough to vaccinate almost one in five people worldwide. The company has promised to make the vaccine globally available by at least July 2021 and in poorer countries around the world on a permanent basis.
“This is very good news for the world,” said Stephen Evans, Professor of Pharmacoepidemiology at the London School of Hygiene and Tropical Medicine, of the approval of the British regulators. “It makes the global approach to a global pandemic much easier.”
For British Prime Minister Boris Johnson, who has come under fire for dealing with the pandemic, the introduction of Oxford-AstraZeneca could bring some relief. The government practically closed more than three-quarters of England on Wednesday and delayed the reopening of secondary schools in January.
Since Pfizer’s vaccine was approved on December 2, the UK has vaccinated 617,000 people with it. 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.