General Gustave Perna, chief operating officer for the Defense Department’s Project Warp Speed, speaks during an Operation Warp Speed vaccine summit at the White House in Washington, D.C., U.S., on Tuesday, Dec. 8, 2020.Al Drago | Bloomberg | Getty ImagesU.S. officials said the federal government plans to start distributing 2.9 million Covid-19 vaccine doses by the end of this week once the Food and Drug Administration grants emergency clearance for Pfizer and BioNTech’s vaccine, which could come as early as Thursday or Friday. Gen. Gustave Perna, who oversees logistics for President Donald Trump’s vaccine program Operation Warp Speed, said an additional 2.9 million doses will be set aside for patients to get their second shot. Pfizer’s vaccine requires two doses administered three weeks apart. The government has also set aside a reserve of 500,000 doses in case of an emergency or manufacturing hiccup, he said.Setting spare doses aside is “good Army general officer planning,” Perna said Wednesday during a press briefing on Covid vaccine distribution, “so that we make sure that in case we need to react to some situation we had some reserves.”Eventually, the federal government and states will be more “confident” in the distribution process of the vaccine and a reserve will no longer be necessary, Dr. Moncef Slaoui, who is leading Operation Warp Speed, said at the same press briefing. “That is the method that we’re using for the initial distributions,” he added.The officials said the initial doses would go to 64 jurisdictions as well as five federal agencies – the Bureau of Prisons, Department of Defense, Department of State, Indian Health Service and Veterans Health Administration. The Department of Defense is slated to start distributing its first 44,000 doses of Pfizer’s vaccine as early as next week, the Pentagon said Wednesday.Doses of the vaccine will be limited as manufacturing ramps up, with officials predicting it will take months to immunize everyone in the U.S. who wants to be vaccinated. Slaoui has previously said the U.S. should be able to distribute enough vaccine doses to immunize 100 million Americans by the end of February, nearly a third of the U.S. population. He has said the entire U.S. population could be vaccinated against Covid-19 by June.Slaoui told reporters Wednesday that the government might be willing to push more Covid vaccine to the public without holding second doses “by the middle of the month of January or early February, when we’ve had five, six weeks of rolling, high-cadence manufacturing, and that we see that things are rolling perfectly.”He said last week that there is a chance the U.S. could have more doses than expected later next year if Johnson & Johnson’s potential vaccine is authorized, adding he expects the company to release key late-stage trial data in January. Officials expect to be distributing vaccines from Pfizer and Moderna by the end of this year.The briefing Wednesday comes a day before an FDA panel is scheduled to vote on whether to recommend the approval of Pfizer’s vaccine for emergency use, the last step before the FDA gives the final OK for public distribution. If the meeting goes well and the Vaccines and Related Biological Products Advisory Committee formally recommends the vaccine, the FDA could announce its authorization “in days,” Health and Human Services Secretary Alex Azar said Wednesday.The vaccine is expected to be distributed in phases, with the Centers for Disease Control and Prevention asking states to prioritize health-care workers and nursing homes first.States had already submitted early plans to the CDC on how they intend to inoculate some 331 million Americans against Covid-19 once a vaccine is approved. The CDC has allocated $200 million to jurisdictions for vaccine preparedness, though much of that funding hasn’t trickled down to the local level.Last Friday, all 64 states, territories and other jurisdictions and five federal agencies locked in their plans to distribute Pfizer’s vaccine, Perna said Wednesday. As many as 36 states have told the CDC that they want initial dosage to go to long-term health-care facilities, he added.