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LONDON, March 23 (Reuters) - AstraZeneca will
publish up-to-date results from its latest COVID-19 vaccine
trial within 48 hours after U.S. health officials said the
drugmaker's analysis of the shot's efficacy may not have been
based on all the available data.
The rare public rebuke marks the latest setback for the
vaccine which was hailed as a milestone in the fight against the
COVID-19 pandemic but has since been dogged by questions over
its effectiveness and possible side effects.
AstraZeneca said results it published on Monday giving the
shot an efficacy rate of 79% were based on an interim analysis
of data through Feb. 17 and it would now "immediately engage"
with the panel monitoring the trial to share its full analysis.
The Anglo-Swedish drugmaker said on Tuesday it had reviewed
the preliminary assessment of its full, or primary, analysis and
found it to be consistent with the interim report.
Its shares were down 2.5% in London trading.
The U.S. National Institute for Allergy and Infectious
Diseases (NIAID) said on Monday that the board charged with
ensuring the trial's accuracy had expressed concern the company
may have given an incomplete view of the shot's effectiveness.
Anthony Fauci, director of the NIAID, said the whole issue
was a really unfortunate unforced error.
"This is very likely a very good vaccine and this kind of
thing does ... nothing but really cast some doubt about the
vaccines and may contribute to the hesitancy," he told "Good
Morning America" on ABC News.
"The data really are quite good but when they put it into
the press release it wasn't completely accurate," he said. "We
have to keep essentially trying as hard as we can to get people
to understand that there are safeguards in place."
'NEGATIVE REPORTS'
Besides being 79% effective in stopping symptomatic illness
in the trial in the United States, Chile and Peru, the data also
showed the shot was 100% effective against severe or critical
forms of the disease and posed no increased risk of blood clots.
The new doubts about the shot's efficacy, however, coincide
with its rollout in dozens of countries and clouds the timeline
for its emergency use authorization in the United States.
"This is indeed an extraordinary act. The negative reports
about this vaccine do not stop, although my assessment is that
it is well tolerated and safe, but clearly less effective than
the two mRNA vaccines," Peter Kremsner, from the University
Hospital in Tuebingen, Germany.
Rival vaccines from Pfizer/BioNTech and
Moderna that use so-called mRNA technology produced
efficacy rates of about 95% each, far above the 50% benchmark
set by global regulators.
The panel monitoring the AstraZeneca trial, the Data and
Safety Monitoring Board, is organized by NIAID and its role is
to provide study oversight and evaluate clinical data to ensure
safe and ethical conduct of the study.
AstraZeneca's COVID-19 shot has faced questions since late
last year when the drugmaker and Oxford University published
data from an earlier trial with two different efficacy readings
as a result of a dosing mistake.
Later analysis suggested the dosing interval rather than the
amount of dose administered was responsible for the difference.
CONFIDENCE HIT
Confidence in the vaccine took a further hit this month when
more than a dozen countries, mostly in Europe, temporarily
suspended the shot after reports linked it to a rare blood
clotting disorder in a very small number of people.
The European Union's drug regulator said last week it was
safe but an opinion poll on Monday showed Europeans remained
skeptical about its safety.
The latest trial data, which has yet to be reviewed by
independent researchers, was based on 141 infections among
32,449 participants.
Analysts had noted AstraZeneca's achievement of producing
strong trial data against a backdrop of more infectious variants
spreading in the United States and other countries.
Stephen Evans, a pharmacoepidemiology professor at London
School of Hygiene & Tropical Medicine, said the up-to-date data
request may have to do with efficacy readings from recent cases,
which may include new variants and thus lower protection rates.
"The other vaccines may also show such reduced efficacy and
we don't know by how much. It does not leave me concerned
particularly unless they had found a safety issue that was being
hidden, which does not appear to be the case."
The AstraZeneca vaccine is seen as crucial in tackling the
spread of COVID-19 across the globe because it is easier and
cheaper to transport than rival shots.
It has been granted conditional marketing or emergency use
authorization in more than 70 countries.
Many countries are relying heavily on it to end the
pandemic, and several state leaders have taken the shot to boost
confidence in the vaccine including South Korea's President Moon
Jae-in who received it on Tuesday.
(Reporting by Miyoung Kim in Singapore; Additional reporting by
Shubham Kalia in Bengaluru, Ludwig Burger in Frankfurt and Kate
Kelland in London; Editing by Edwina Gibbs, Josephine Mason and
David Clarke)
