Speaking during a CVS Health Live event that was posted on Facebook, the head of the pharmaceutical corporation, Albert Bourla, said new data shows that Pfizer's vaccine is effective against a concerning variant of the coronavirus that was first seen in South Africa.
"Protection goes down by time but still in six months it's still extremely, extremely high," Bourla said. "If you ask me, I think that there will be a need, based on these data, for revaccinations."
It was still unclear how often people would have to receive booster shots, the CEO said, adding that "a likely scenario is that there will be likely a need for a third dose somewhere between six and 12 months and then from there, there will be an annual re-vaccination. But all this needs to be confirmed."
He noted that in a pandemic, "you are as protected as your neighbor."
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"You can't achieve protection if all the U.S. people are vaccinated but none of the (people in) Latin America -- or very few in Latin America or very few in Africa," he said, emphasizing the importance that all countries get their citizens vaccinated.
More than 30% of U.S. adults have been fully vaccinated, according to the most recent data from the Centers for Disease Control and Prevention, and a CNN analysis has some states being able to vaccinate all willing adults by June.
The CNN Wire contributed to this report.