The real-world findings suggest the shot could seriously reduce asymptomatic transmission.
It's also introducing a strike system that can lead to permanent account suspension.
He says Americans should be hopeful but not complacent.
It's a partial reversal from Facebook's previous position on vaccine misinformation.
But older Americans are most likely to die.
Viruses mutate and evolve and the coronavirus is no different.
There's no evidence yet that vaccines "prevent people from actually getting the infection," official warns.
Adults over 75 are eight times more likely to be hospitalized after contracting the virus.
Italy and Austria are the latest countries to restrict flights from the U.K.