The biggest problem so far has not been a lack of vaccine, but the difficulties that state and local governments face in distributing the doses they have. Capacity and logistics, not shortages, are keeping vaccines from being administered.
Dr. Leana S. Wen, an emergency physician and public health expert at the George Washington University School of Public Health, said she was surprised and concerned about Mr. Biden’s new strategy.
“This is not the problem we’re trying to solve right now,” Dr. Wen said.
Speaking at a news briefing on Friday, Dr. Stephen M. Hahn, the F.D.A. commissioner, urged states that have used only a small part of their supply to begin vaccinating lower-priority groups, while still observing government guidelines. Most states are still prioritizing frontline health care workers and older Americans in group residential settings.
Expanding the targeted groups “will go a long way toward using these vaccines appropriately and getting them into the arms of individuals,” Dr. Hahn said.
Biden advisers have not discussed the rest of their plan to overhaul vaccine distribution; they say more details will be released next week. Mr. Biden has always promised a far more muscular federal response than Mr. Trump’s leave-it-to-the-states approach, and he has been outlining his vision in public appearances and interviews with local radio stations while campaigning early this week for Georgia’s Democratic Senate candidates.
“Our plan is going to focus on getting shots into arms, including by launching a fundamentally new approach, establishing thousands of federally run or federally supported community vaccination centers of various size located in places like high school gymnasiums and N.F.L. stadiums,” Mr. Biden said during an interview with WFXE-FM in Columbus, Ga.
“And,” he went on, “they can be run by federal staff, contractors, volunteers, including FEMA, you know, the emergency management group, the Centers for Disease Control, the U.S. military, the National Guard.”