The two known affected shipping hubs include FedEx facilities in Memphis, Tenn., and Louisville, Ky., according to the CDC. It is unclear how many vaccine doses are affected by shipment delays, but officials from numerous states said they were expecting delays, including Colorado, Illinois, Minnesota and Texas.
Kris Ehresmann of the Minnesota Department of Health said health care providers in the state may have to reschedule appointments because of the delays.
Meanwhile, a number of cities across the country, including Chicago, Memphis and Dallas, closed vaccination sites because of the winter storms.
The news comes as the Biden administration on Tuesday announced that it will increase weekly vaccine allocations to states by 23 percent, from 11 million doses to 13.5 million.