Within the first distribution push, 6.four million doses of Pfizer’s vaccine can be shipped throughout the U.S.

Around mid-December, 6.4 million doses of Pfizer’s Covid-19 vaccine will be shipped in a first foray into the United States after receiving an expected emergency clearance. Those in charge of Operation Warp Speed, the government’s push to speed up a vaccine, said on a call to reporters on Tuesday.

The first doses expected to go to healthcare workers and possibly some other vulnerable groups will be assigned to all 50 states and eight territories and six major metropolitan areas. The amounts vary based on how many adults live in each jurisdiction.

“We wanted to keep it simple,” said Alex M. Azar II, the secretary for health and human services.

Officials opted for this allocation formula as opposed to one that would prioritize the hardest-hit parts of the country, in part because the virus is spreading rapidly across the country, Azar said.

Operation Warp Speed ​​announced late Friday night how many doses they would receive on the first push to aid them in their planning, officials said Tuesday. Governors and other local leaders will be responsible for deciding where the broadcasts should go.

Pfizer ships the vaccine doses via UPS and FedEx in special refrigerators filled with dry ice and containing at least 975 doses. These must be used up within a few weeks or kept in an ultra-cold freezer for up to six months.

Pfizer’s vaccine, which was jointly developed with German company BioNTech, was found to be 95 percent effective in a late-stage study earlier this month. An advisory committee of the Food and Drug Administration is scheduled to meet on December 10 to discuss the data from Pfizer’s clinical trial and to vote on whether the agency should recommend approval.

From there, it’s not clear how long it will take to make a decision. The agency could take “days” to consider approving the vaccine, said FDA Commissioner Dr. Stephen Hahn in an interview with USA TODAY published on Tuesday.

But Moncef Slaoui, head of Operation Warp Speed, said during a television appearance on CNN’s State of the Union on Sunday that the first doses could be given as early as December 11th. Federal health officials said the first Americans would start getting vaccinated within 24 hours of approval.

Another leading vaccine developer, Moderna, is expected to soon follow Pfizer’s lead in applying for an emergency permit for its vaccine candidate, which, according to early analysis, was 94.5 percent effective.

The path to the US is less clear for AstraZeneca and the University of Oxford, which announced Monday that they have been focusing on a promising dosing schedule for their vaccine candidate.

All three vaccines require people to receive two doses several weeks apart.

After the initial sales spurt, vaccine shipments will be sent weekly to states and other jurisdictions. Federal officials have announced they will have 40 million doses of Covid-19 vaccines available by the end of the year.