• The U.S. stands ready to deliver up to 4 million doses of Johnson & Johnson's Covid-19 vaccine as soon as next week if the FDA authorizes the shot for emergency use, a top health official said.
• The administration plans on allocating between 3 million and 4 millions doses of J&J's one-shot inoculation, Jeff Zients, President Joe Biden's Covid czar, said.
• Zients said the administration will waste "no time" getting the vaccine into Americans' arms, and is ready to deliver the shots "without delay."

The United States stands ready to deliver up to 4 million doses of Johnson & Johnson's coronavirus vaccine as soon as next week if the Food and Drug Administration authorizes the shot for emergency use, the Biden administration's Covid-19 response team said Wednesday.

"The governors are carefully planning their efforts and are getting ready for the possible new vaccine," Jeff Zients, President Joe Biden's Covid czar, said at a news briefing. "If authorized, we're ready to roll out this vaccine without delay."

"If the EUA is granted, we will waste no time getting this lifesaving vaccine into the arms of Americans," he said, referring to the emergency use authorization that would allow the U.S. to start distributing the shots.

The administration plans on allocating between 3 million and 4 millions doses of J&J's one-shot Covid vaccine next week if the FDA grants the EUA, which could come as soon as this weekend. A senior administration official told CNBC on Tuesday that states will be given 2 million doses if authorized.

Zients said that the remaining allocations will mostly go to retail chain pharmacies and community health centers, which are sent doses directly from the federal government alongside the states.

J&J aims to deliver 20 million doses by the end of March, Zients said, and the administration is working with the company "to accelerate the pace and time frame by which they deliver the full 100 million doses" by the end of June.

Earlier on Wednesday, FDA staff endorsed J&J's vaccine for emergency use. The staff report is meant to brief the agency's Vaccines and Related Biological Products Advisory Committee, which will meet Friday to review J&J's request for emergency use authorization.

If cleared, the shot would become the third vaccine given authorization in the U.S. behind Pfizer-BioNTech and Moderna.

Federal and state health officials were expecting a boost in the nation's vaccine supply if J&J's shot were to receive authorization, but top health officials have learned in recent weeks that the company will not have "a big inventory" to start.

"I'm a little disappointed that the number of doses that we're going to get early on from J&J are relatively small, but as we get further into the spring there will be more and more," White House Chief Medical Advisor Dr. Anthony Fauci said last week.

The Biden administration has gradually increased the number of doses it allocates to states each week. On Tuesday, White House press secretary Jen Psaki said the U.S. will now supply states with 14.5 million doses of coronavirus vaccine per week, up from 8.6 million when Biden took office.

Zients said during Wednesday's briefing that the administration has also caught up on a backlog of 6 million Covid-19 vaccines that were delayed last week after massive winter storms across the Midwest and Texas created bottlenecks in their delivery channels.

The U.S. has delivered more than 82 million doses of Covid-19 vaccines so far, and has administered just over 65 million of them, according to recent data from the Centers for Disease Control and Prevention.