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President Biden delivered some exciting news Tuesday, promising the United States will have enough COVID-19 vaccine supply by the end of May for every American adult to get a shot.

Just a few weeks ago, Biden had set the end of July as the target date for universal availability, but the timeline has been expedited, largely thanks to the addition of the Johnson & Johnson vaccine to the arsenal. Biden couldn't account for the third shot when he last addressed the situation because it hadn't been granted emergency approval by the Food and Drug Administration at the time.

But that's where the caveats come in. Tuesday's announcement was primarily focused on an increase in supply, which is just one aspect of vaccine distribution. At least some of the hurdles that the U.S. currently faces in terms of actually getting people vaccinated could still be there in May. For example, Biden himself acknowledged that "it's not enough to have the vaccine supply, we need vaccinators — people to put the shots in people's arms," and, as Stat News points out, the president didn't highlight any new efforts to increase the number of vaccinators.

That said, even though it's still unclear if every adult will actually be able to receive a vaccine by the end of May, the U.S. does appear to be consistently increasing its vaccination pace, so the supply increase may have come at the right time.