How long does protection from COVID-19 vaccines last?
Given that COVID-19 vaccines were สล็อต เกมเดิมพัน SLOTXO การันตีการจ่ายเงิน granted authorisation
for emergency use relatively recently, experts are still studying vaccinated people to see when
protection might wear off.
How well the vaccines work against emerging variants of the coronavirus will also determine if,
when and how often additional shots might be needed.
“We only have information for as long as the vaccines have been studied," said Deborah Fuller,
a vaccine researcher at the University of Washington.
“We have to study the vaccinated population and start to see, at what point do people become
vulnerable again to the virus?”
So far, Pfizer's ongoing trial indicates the company's two-dose vaccine remains highly effective for
at least six months, and likely longer. Pfizer's chief executive Albert Bourla said on Apr 1 that people
will "likely" need a third booster dose within 12 months and could need annual shots.
Initial data has also shown that vaccines from Moderna retain most of their effectiveness for at least
six months, though for how much longer has not been determined. Immunity should last for at least
a year, the company said in January.
Antibodies also don't tell the whole story. To fight off intruders like viruses, our immune systems also
have another line of defense called B and T cells, some of which can hang around long after antibody
levels dwindle. If they encounter the same virus in the future, those battle-tested cells could
potentially spring into action more quickly.
Even if they do not prevent illness entirely, they could help blunt its severity. But exactly what role
such “memory” cells might play with the coronavirus - and for how long - isn’t yet known.
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