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HEALTH-VIRUS-BRITAIN-VACCINE-ASTRAZENECA
AstraZeneca says its vaccine needs ‘additional study’
LONDON, Nov 27, 2020 (BSS/AFP) – The head of British drug manufacturer
AstraZeneca said on Thursday further research was needed on its Covid-19
vaccine after questions emerged over the protection it offers, but the
additional testing is unlikely to affect regulatory approval in Europe.
AstraZeneca and its partner, the University of Oxford, announced on Monday
that it was seeking regulatory approval for the vaccine after it showed an
average 70-percent effectiveness.
That rate jumped to 90 percent when an initial half-dose then a full dose
was given, similar to that in rival vaccines in development by
Pfizer/BioNTech and Moderna.
But US scientists have said the higher rate of effectiveness came during
tests in people aged 55 and under, and was discovered by accident during the
clinical trials.
The head of the Oxford Vaccine Group, Andrew Pollard, said this week that
further evidence will be available next month, but the result was still
“highly significant”.
“Now that we’ve found what looks like a better efficacy, we have to
validate this, so we need to do an additional study,” AstraZeneca chief
executive Pascal Soriot told Bloomberg.
He said he expected that to be another “international study but this one
could be faster because we know the efficacy is high, so we need a smaller
number of patients”.
The additional trial was not likely to delay regulatory approval in Britain
and the European Union, Soriot said.
There are high hopes for the AstraZeneca/Oxford vaccine, which Pollard has
hailed as a “vaccine for the world” given that it could be cheaper to make,
and easier to store and distribute.
It can be stored, transported and handled at normal refrigerated conditions
of between two and eight degrees Celsius (36-46 Fahrenheit) for at least six
months.
Pfizer/BioNTech’s offering requires temperatures of -70C, driving up costs
and potentially making it out of reach for lower and middle-income countries.
AstraZeneca/Oxford has also promised to provide its vaccine to the
developing world on a non-profit basis.
– Wait and see –
The World Health Organization said it looked forward to the full
publication of the data from the trial.
“On a review of the detailed data, we will be better positioned to
understand the vaccine performance,” it said.
The chief medical officer for England, Chris Whitty, also cautioned against
drawing premature conclusions, and urged patience until the data were
published in peer-reviewed journals.
“It’s always a mistake to make too many judgments early and in particular
before the independent regulator has had a chance to look at the results,” he
told a news conference.
Helen Fletcher, professor of immunology at the London School of Hygiene and
Tropical Medicine, said the safety data available on the vaccine had been
“very robust”.
“It’s possible that a lower initial vaccine dose could result in higher
vaccine efficacy… More is not necessarily better when it comes to vaccines
and immunotherapies,” she said.
“It’s also possible that a strong immune response to the first vaccine
could effectively block an immune response to the second shot of the same
virus.”
Fletcher’s colleague, professor of pharmacoepidemiology Stephen Evans, said
speculation about the age distribution in the trials was “not useful to
anyone”.
“We have good grounds for trusting that the regulation in this high-profile
area will be done as carefully or more carefully for these vaccines than for
any others in the past,” he said.
Gillies O’Bryan-Tear, from the UK Faculty of Pharmaceutical Medicine, said
“the eventual efficacy rate may change”, but “the validity of the low
dose/high dose group results are unlikely to be questioned”.
“Even if they (the regulators) decided to ignore the results of the low
dose/high dose group, the study of the high dose/high dose patients will
still be strongly significant, but I think that it unlikely,” he said.
BSS/AFP/GMR/0938 hrs