President Joe Biden reassured Americans the United States had enough coronavirus vaccines, even without the Johnson & Johnson vaccine federal health officials paused Tuesday.

“There is enough vaccine; that is basically 100 percent unquestionable, for every single, solitary, American,” Biden said.

The president spoke to reporters briefly in the Oval Office Tuesday and said the United States already purchased 600 million doses of the mRNA vaccines from Pfizer and Moderna. He indicated the country did not even need vaccines from Johnson & Johnson and AstraZeneca.

Dr. Anthony Fauci said Tuesday he could not say definitively whether the Johnson & Johnson vaccine would return to market.

“I wouldn’t want to speculate as to what would happen often when you see things like this, that you pause and come back. Whether or not that happens now I can’t guarantee it,” he said.

Fauci said the decision on the vaccine would take “days to weeks” to review.

Federal health officials detailed their decision to pause the Johnson & Johnson vaccine, due to “extremely rare” incidents of recipients developing blood clots.

“It’s plainly obvious to us already that what we’re seeing with the [J&J] vaccines looks very similar to what was being seen with the Astra-Zeneca vaccine,” Dr. Peter Marks, the director of the Food and Drug Administration’s Center for Biologics Evaluation and Research, told reporters in a conference call detailing the decision.

Marks said the Astra-Zeneca is a chimpanzee adenoviral vectored vaccine and the [J&J] is a human adenoviral vectored vaccine, different from the Pfizer and Moderna mRNA vaccines.

He cautioned that officials still had to come to a scientific conclusion about the Johnson & Johnson vaccine.

“I think we can’t make some broad statement yet, but obviously they are from the same general class of viral vectors,” he said.