New research has identified unusual antibodies that appear
to have caused, in rare cases, serious and sometimes fatal blood clots in
people who received the COVID vaccine made by AstraZeneca.
اضافة اعلان
Exactly why the rare reactions to the vaccine occurred is
still a mystery.
Scientific teams from Germany and Norway found that people
who developed the clots after vaccination had produced antibodies that
activated their platelets, a blood component involved in clotting. The new
reports add extensive details to what the researchers have already stated
publicly about the blood disorder.
Younger people appear more susceptible than older ones, but
researchers say no preexisting health conditions are known to predispose people
to the rare reaction. That is worrisome, they say, because there is no way to
tell if an individual is at high risk.
Reports of the clots have already led a number of countries
to limit AstraZeneca’s vaccine to older people, or to stop using it entirely.
These cases have dealt a crushing blow to global efforts to halt the pandemic,
because the AstraZeneca shot — easy to store and relatively cheap — has been a
mainstay of vaccination programs in more than 100 countries.
The European Medicines Agency, the regulator for the
European Union, has emphasized repeatedly that the clotting disorder is rare,
and that the vaccine’s benefits far outweigh its risks. But when a side effect
has the potential to be devastating or fatal — like the blood clots in the
brain linked to this vaccine — some regulators and segments of the public are
finding that the risk is unacceptable, even if it is extremely rare.
As of Sunday, European regulators had received reports of
222 cases of the rare blood-clotting problem in Britain and the 30-nation
European Economic Area (the European Union plus Iceland, Norway and
Liechtenstein). They said that about 34 million people had received the
AstraZeneca vaccine in those countries, and that the clotting problems were
appearing at a rate of about 1 in 100,000 recipients.
European regulators said that as of March 22, they had
carried out detailed reviews of 86 cases, 18 of which had been fatal.
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