By Joseph Walker and Jenny Strasburg
LONDON -- The U.K. authorized a Covid-19 vaccine developed by
the University of Oxford and AstraZeneca PLC, opening the door for
the rollout of millions of doses in a country where infections have
surged amid a more infectious variant of the virus.
U.K. health officials also recommended a delay of up to three
months between both doses of the vaccine, guidance that also
applies to the shot developed by Pfizer Inc. and BioNTech SE that
was authorized in the U.K. earlier this month. The delay will allow
inoculations to reach more people more quickly as the new variant
pushes new cases to records and hospitalizations soar.
The green light represents the third emergency-use approval of a
Western-developed vaccine this month and comes as cases are rising
sharply in Europe and the U.S., which has now reported its first
case of the new variant. The Pfizer-BioNTech shot and one developed
by Moderna Inc. have been cleared in the U.S.
The Oxford-AstraZeneca vaccine stands out on price, convenience
and global ambition. AstraZeneca has promised to make as many as
three billion doses available in 2021 -- more than any other
Covid-19 vaccine maker -- and at a cheaper price. The U.K. company
says it won't profit from the shot during the pandemic, or ever in
the case of poorer countries. The vaccine also can be transported
and stored for months with normal refrigeration, making it easier
to distribute where people and health-care networks are sparse or
underfunded. The two other Western vaccines in use require
ultracold temperatures for all but a few days or weeks.
AstraZeneca's shot -- less effective in clinical trials than its
rivals' injections -- won't be available in the U.S. until the Food
and Drug Administration reviews large-scale trials still being
conducted there and decides whether to authorize its use.
The mutated virus recently triggered travel bans from some
nations on visitors and goods from Britain, ratcheting up the
political urgency for a speedy vaccine rollout here. The government
has said that more than 600,000 doses of the Pfizer-BioNTech
vaccine have been administered.
Scientists have said that the three Covid-19 vaccines authorized
by Western countries so far should be similarly effective against
the new variant as they have been in clinical trials, a view
AstraZeneca executives share, according to a person familiar with
the matter. The new variant could be as much as 70% more
transmissible than more established forms of Covid-19, government
officials say.
The U.K. medicines regulator said the vaccine can be
administered to people 18 years and older. The authorization clears
the use of two standard vaccine doses, a regimen that was 62%
effective in preventing symptomatic Covid-19 in an interim analysis
of trials involving about 11,600 people in the U.K. and Brazil.
In the same study, a small subset of volunteers of age 55 and
younger were given a half-dose shot followed by a standard dose.
That subset showed a higher protection rate of 90%. The U.K.
government hasn't authorized the use of the half-dose regimen.
"We felt the results were not borne out by the full analysis,"
Munir Pirmohamed, a pharmacologist who chairs the government's
advisory group that advised on the regulator's recommendations,
said in a media briefing Wednesday.
U.K. officials said they authorized the vaccine Tuesday and
released the first batches that night.
They advised that no preference generally should be given
between the two vaccines so far authorized by the U.K. The higher
efficacy shown by the Pfizer vaccine isn't directly comparable with
that of the Oxford-AstraZeneca shot, officials said, because of
scientific and clinical-trial differences.
AstraZeneca and U.K. health officials said the two-dose regimen
is flexible in terms of when the second dose should be given,
anywhere from four weeks to 12 weeks after the first dose.
Delaying the second dose would help stretch supplies of the
vaccine so more Britons get a first shot sooner. But the vaccine's
full protection -- benefits shown in clinical trials to prevent
hospitalization -- only kicks in after the second dose.
U.K. health officials said Wednesday the updated second-dose
guidance also applies to the Pfizer-BioNTech shot already being
administered in the country. Previously, the second dose was
recommended 21 days after the first. U.K. officials on Wednesday
changed that to "within 12 weeks, " saying the change was based on
the latest scientific advice. The vaccine's makers have said full
protection doesn't start until at least seven days after the second
dose.
Pfizer has promised the U.K. millions more doses by the end of
the year, but the AstraZeneca and Oxford shot -- made at facilities
in the country and elsewhere -- promises to quicken the rate of
inoculations by the country's state-run health-care system. The
National Health Service will determine which shot to provide people
depending on supply.
AstraZeneca said Wednesday it will supply millions of doses in
the first quarter of next year, without specifying an exact number.
The U.K. has ordered up to 100 million doses of the vaccine, enough
for 50 million people.
Government advisers behind the authorization said the 90%
efficacy shown in the half-dose regimen might have been caused by
the longer period between the first and second doses in that trial
subgroup, rather than the half-dose itself. They said the analysis
of the half-dose subgroup helped lead to the U.K. government's
decision to recommend up to 12 weeks between doses.
The advisers said for the full-dose regimen, immunity kicks in
roughly three weeks after the first dose. They estimated 70%
effectiveness in the vaccine during the period from three weeks
after the first dose, through the next three months. They said it
isn't clear whether that number will hold up in fuller clinical
trials.
It is unclear how quickly other nations might authorize the
vaccine. A large clinical trial is under way in the U.S., where
AstraZeneca executives expect to have full trial data to submit by
February, according to a person familiar with the matter. They have
been submitting batches of data to European regulators and are
poised for potential authorization across the European Union by
February, the person said.
Oxford and AstraZeneca emerged early this year as front-runners
in the race to develop a Covid-19 vaccine before falling behind
competitors that were able to complete clinical trials faster.
Developed by scientists at Oxford's Jenner Institute, the vaccine
uses a weakened cold virus to courier genetic material from the
coronavirus into cells and trigger immunity.
AstraZeneca agreed in April to co-develop Oxford's technology
and distribute it around the world at no profit during the
pandemic. By November, the company had agreements to supply three
billion doses to every region in the world.
The partners have faced setbacks along the way to Wednesday's
milestone. In May, they launched a combined Phase 2 and 3 clinical
trial in the U.K. aimed at enrolling more than 10,000 volunteers
and obtaining initial results by August. But the study progressed
slower than hoped for initially, partly because of relatively low
infection rates in the U.K. for much of the summer and fall.
By the time AstraZeneca launched a planned Phase 3 U.S. study of
30,000 volunteers in late August, the company was trailing behind
Pfizer and Moderna, which had begun similarly sized studies a month
earlier. Within two weeks, AstraZeneca paused all its studies
globally after a U.K. volunteer had an unexplained illness. U.K.
regulators allowed studies to resume quickly, but the U.S. trial
remained grounded for more than six weeks before U.S. regulators
lifted the hold in October.
Write to Joseph Walker at joseph.walker@wsj.com and Jenny
Strasburg at jenny.strasburg@wsj.com
(END) Dow Jones Newswires
December 30, 2020 11:13 ET (16:13 GMT)
Copyright (c) 2020 Dow Jones & Company, Inc.
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