“My general feeling is that given the contractual relationships that we have with a number of companies, that we have enough vaccine to fulfill all of our needs without invoking AstraZeneca,” he said.

The nation’s top infectious disease expert added that the US possibly also has enough vaccine supply for booster shots in the fall.

“If you look at the numbers (of doses) that we’re going to be getting … it is likely that we can handle any boost that we need, but I can’t say definitely for sure,” he told Reuters.