Pakistan, April 16 -- Pfizer CEO Albert Bourla said that it is highly likely that people will require a third vaccine shot within 12 months of being fully vaccinated.

Bourla said it is possible people will need to get vaccinated against the coronavirus annually.

"We need to see what would be the sequence, and for how often we need to do that, that remains to be seen," Bourla told CNBC in an interview recorded on April 1.

"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 revaccination, but all of that needs to be confirmed," he said, adding that variants will play a "key role."

"It is extremely important to suppress the pool of peopl...