Last checked at 
(Updates to include Pfizer data from interim analysis)
By Carl O'Donnell
NEW YORK, Nov 9 (Reuters) - Drugmakers and research centers
around the world are working on COVID-19 vaccines, with large
global trials of several of the candidates involving tens of
thousands of participants well underway.
The following is what we know about the race to deliver
vaccines to help end the coronavirus pandemic that has claimed
over 1.25 million lives worldwide:
Who is furthest along?
U.S. drugmaker Pfizer Inc and German partner
BioNTech SE are the first to release data
showing that their vaccine worked in a large, late-stage
clinical trial.
The next data releases will likely be from U.S. biotech firm
Moderna Inc, possibly in November, and from
Britain-based AstraZeneca Plc with the University of
Oxford in November or December. Johnson & Johnson says
it is on track to deliver data 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 is Pfizer ahead with its data?
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 said its interim analysis was conducted after 94
participants in the trial developed COVID-19.
AstraZeneca said last week a slowdown in infections during
the summer is delaying data analysis for its UK trial.
COVID-19 cases, however, soared in October and early
November, setting daily records in the United States and Europe.
How well are the vaccines supposed to work?
The World Health Organization has recommended a minimum
standard for effectiveness of at least 50%. The United States
and some other regulators are following that guideline – which
means there must be at least twice as many infections among
volunteers who received a placebo as among those in the vaccine
group. The European Medicines Agency has said it may accept a
lower efficacy level.
Pfizer said its vaccine is more than 90% effective against
COVID-19.
When will regulators rule on safety and efficacy?
Regulators review vaccines after companies submit
applications seeking either emergency use authorization (EUA) or
formal approval.
The earliest the U.S. Food and Drug Administration could
make a decision is in December because Pfizer/BioNtech and
Moderna do not expect to have enough safety data until the
second half of November. The FDA has asked companies to watch
trial participants for side effects for two months after
receiving a final vaccine dose.
Regulators for Europe, the United Kingdom and Canada are
considering data on a rolling basis, as it becomes available.
They expect to conduct expedited reviews as well. It is not
clear when companies will submit efficacy data to these agencies
or when the agencies would make a decision.
Could these be the first widely available 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 those from
China National Biotec Group (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
Ivanova in Moscow; Editing by Caroline Humer, Bill Berkrot,
Edwina Gibbs and David Clarke)
