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 The following is what we know about the race to deliver vaccines to
help end the coronavirus pandemic that has claimed over a million
lives worldwide:
Who is furthest along?
U.S. drugmaker Pfizer Inc with German partner BioNTech SE, and U.S.
biotech Moderna Inc could have early data in November. Britain-based
AstraZeneca Plc, in conjunction with University of Oxford, and
Johnson & Johnson say they are on track to deliver data for their
vaccines this year.
What happens in these trials?
The companies are testing their vaccines against a placebo -
typically saline solution - in healthy volunteers to see if the rate
of COVID-19 infection among those who got the vaccine is
significantly lower than in those who received the dummy shot.
Why are data reports delayed beyond original predictions?
The trials rely on subjects becoming naturally infected with the
coronavirus, so how long it takes to generate results largely
depends on how pervasive the virus is where trials are being
conducted. Each drugmaker has targeted a specific number of
infections to trigger a first analysis of their data.
Pfizer, for instance, believes it may know if its vaccine works once
32 people contract COVID-19 in the 44,000-person trial, as long as
the overwhelming majority of those infected had received the
placebo.
But drugmakers have said an insufficient number of infections prior
to the recent spikes in cases slowed their ability to present data
earlier. Pfizer in October said it did not expect to have usable
trial data until late November due to slow infection rates. It had
previously suggested that would happen in October.
AstraZeneca said a slowdown in infections during the summer delayed
its UK trial and that it expected to have results by the end of the
year. Its timeline was also extended by a pause to investigate an
illness in a UK trial participant.
After a slowing of infections in late summer and early autumn,
COVID-19 cases were rampant again in October and early November,
setting daily records in the United States and Europe as the weather
cooled and people moved indoors. Experts have suggested that trial
participants may also have been more careful to avoid contracting
COVID-19 than the general population knowing they may have received
a placebo.
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How will we know if the vaccine works?
The United States, the European Union, the United Kingdom and the World Health
Organization have all set similar minimum standards for effectiveness. Some
regulators have said that vaccines must demonstrate at least 50% efficacy -
meaning at least twice as many infections among volunteers who got a placebo as
among those in the vaccine group. The European Medicines Agency has said it may
accept a lower efficacy level.
When will regulators decide?
Regulators will review the vaccines after the companies have enough data to
submit applications seeking emergency use authorization (EUA) or formal
approval. The earliest they could decide is in December because Moderna and
Pfizer/BioNtech do not expect to have enough safety data until the second half
of November. U.S. regulators have asked that participants be watched for side
effects for two months after receiving a final vaccine dose. AstraZeneca could
provide a look at late-stage data by the end of the year. UK officials said
there is a slight possibility they could decide on that vaccine in late
December.
Regulators for Europe, the United Kingdom and Canada are considering data on a
rolling basis, as it becomes available. They expect to do speedy reviews of
initial data for possible emergency use before more traditional lengthy reviews
for formal commercial approvals.
Could these be the first approved coronavirus vaccines?
Yes, although China and Russia are on a similar timeline. China launched an
emergency use program in July aimed at essential workers and others at high risk
of infection that has vaccinated hundreds of thousands of people. At least four
vaccines are far along including from China National Biotec Group [CHNAPF.UL] (CNBG),
CanSino Biologics and Sinovac. Sinovac and CNBG have said to expect early trial
data as soon as November. Russia's Gamaleya Institute has begun a 40,000-person
late-stage trial and is expected to have early data in November. Russia has also
given the vaccine to at least hundreds of "high-risk" members of the general
population.
(Reporting by Carl O'Donnell in New York; Additional reporting by Julie
Steenhuysen in Chicago, Michael Erman in New York, Ludwig Burger in Frankfurt,
Alistair Smout in London and Polina Ivanovo in Moscow; Editing by Caroline Humer
and Bill Berkrot)
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