The changes were unveiled to governors as Biden set a goal of providing at least one shot to 70 percent of adults by July 4, an increase that would account for about 40 million more people in the next two months. That level of coverage could drive down cases sharply, as it did in Britain and Israel. But achieving it, experts said, depends on efficiently delivering shots to places where people are still rolling up their sleeves — or can be persuaded to do so.
“The sooner we get the most people vaccinated not only in our local regions, but around the country, the sooner we will have fewer variants developing and less spread in general,” said David Kimberlin, a pediatric infectious-disease specialist at the University of Alabama at Birmingham. “Now that there are places saying, ‘Our freezers are full, so please don’t send any more,’ there needs to be an ability to reallocate.”
Each state’s share of the total U.S. adult population will still determine weekly allocations. But instead of carrying over unordered doses week to week, the White House will steer untapped vaccine into a federal bank available to states seeking additional supply. Those states will be able to order up to 50 percent above their weekly allocation, while states declining their complete allotments one week will still have access to their entire share the following week.