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LONDON, April 22 (Reuters) - Britain's medicines regulator
on Thursday said there had been 168 major blood clots following
a dose of AstraZeneca's COVID-19 vaccine, a rate of 7.9
clots per million doses, a jump in incidence from the previous
week's figure.
This was up from the 100 cases reported last week, when the
overall case incidence was 4.9 per million doses.
There has been scrutiny of the AstraZeneca vaccine on the
issue of the very rare clots and some countries, including
Britain, have recommended that only people over a certain age
get the shot.
Adam Finn, Professor of Paediatrics at Bristol University,
said the jump in reported cases was expected.
"Cases are being reported reliably and quickly but there are
also cases that occurred previously now being recognised and
reported as well," Finn said.
"I would expect the true number of cases per million doses
of vaccine to become clear fairly soon as these reports
stabilise but it is already clear that it is going to remain a
very rare event."
There have been 21.2 million first doses of AstraZeneca's
shot given in Britain's rollout, with all except one of the side
effect case reports coming after a first dose. A total was not
given for second doses administered.
There were 32 reported deaths from clots in total, compared
to 22 reported last week, but the fatality rate of the reported
clots dropped to 19% from 22%.
Britain has advised that under-30s receive an alternative to
the AstraZeneca-Oxford vaccine, after the MHRA medicine
regulator found there was evidence of a link to rare clots with
low platelet levels.
Officials have emphasised the side effect is "vanishingly"
rare and advised that most people still get the shots. The
preference for under-30s to get a different shot is mainly
informed by that age group's low risk from COVID-19, combined
with Britain's low prevalence of infection.
That differs from several European countries such as France,
which has decided to restrict use of AstraZeneca's shot to
people over 55.
"On the basis of this ongoing review, the advice remains
that the benefits of the vaccine outweigh the risks in the
majority of people," the MHRA said on Thursday, reiterating its
advice for the shot.
(Reporting by Alistair Smout
Editing by Frances Kerry)
