Can Biden pull off 100 million COVID-19 vaccinations in 100 days? Here are facts, data, and viewpoints.

News outlets have been parsing President Joe Biden’s promise of one million COVID-19 shots a day for his first 100 days. Depending on the outlet, the goal is too ambitious, or too modest, or doable but difficult, or already stirring disagreements within Biden’s pandemic response team.

Only one thing is indisputable: Time will tell. April 30 will mark 100 days since Biden was inaugurated, but well before that, it should be clear whether the new administration is on track to fix the chaotic, lagging vaccination rollout it inherited.

Even if that 100-day goal is achieved, it will be only the beginning. Experts estimate that 60% to 70% of the population would need to be vaccinated to extinguish the spread of the coronavirus. Anthony Fauci, who is being retained by Biden as the government’s top infectious-disease adviser, recently raised his estimate to 80% to 90%. Meanwhile, the COVID-19 death toll is 410,000 and counting.

The situation is changing by the hour, but here is an overview:

Yes, judging from the quickening pace of inoculations, and existing and expected deliveries by Pfizer-BioNTech and Moderna, makers of the two authorized vaccines, both of which require two shots.

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In the 40 days since COVID-19 immunization began, 17.5 million doses have gone into arms — less than half of the 37.9 million doses delivered to the states, according to the latest data from the U.S. Centers for Disease Control and Prevention.

However, some states have ramped up enough to accelerate the overall effort. The number of people receiving a first dose has been approaching one million per day in recent weeks, and hit that target five times in the last 10 days, the Washington Post’s vaccination tracker shows.

Meanwhile, Pfizer and Moderna together have pledged to deliver 200 million does by the end of March — more than 18 million doses a week, the New York Times reported Thursday. That would be enough to exceed Biden’s goal.

Other COVID-19 vaccines that are close to seeking federal emergency authorization, notably Johnson & Johnson’s candidate, would further expand supply.

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The Trump administration’s Operation Warp Speed played a vital role in getting vaccines from drawing board to distribution within a year, an unprecedented record. But the states and big cities such as Philadelphia were left to sweat the details of vaccinating a potential pool of 209 million adults, including prioritization criteria, notification systems, the creation and staffing of vaccination sites, and data reporting.

The massive effort got even messier on Jan. 12, eight days before Biden was sworn in. Trump’s health secretary, Alex Azar, and CDC director, Robert Redfield, upended the phased priority system that CDC scientists and the states had spent months developing. Instead of expanding vaccination from frontline health workers and nursing homes to essential workers and those age 75 and up, Azar told the states to push to the front of the line a vast group of people he wanted to be there from the start — people age 65 and over — as well as younger people with chronic health conditions.

Some states — West Virginia, Vermont, Connecticut, and the Dakotas — have done pretty well managing the resulting public confusion and frustration over who should get shots and how to do so. So far, these states have given at least one vaccine dose to more than 6% of their populations, according to the Washington Post tracker.

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In Pennsylvania, which is still trying to set up a statewide vaccine registration system, 4% of residents have gotten at least one shot. In New Jersey, the figure is 4.5%; the Garden State quickly set up a registration website and mass vaccination clinics in places such as shopping malls.

The lack of federal organization and direction has left some states running low on doses, while others still have much of their supply sitting on shelves. It has also led to infighting. For example, the University of Pennsylvania’s medical school announced it would vaccinate academic employees and students who don’t have contact with patients in the second phase of vaccination — a move that Philadelphia says circumvents the city’s prioritization plans.

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Biden’s 198-page pandemic plan, unveiled Thursday, instructs federal agencies to harness the U.S. industrial base by invoking the Defense Production Act if needed to expand the vaccination efforts. Biden’s team is using the DPA to mass-produce a special syringe that can get six doses instead of five from each Pfizer vial, White House chief of staff Ron Klain told MSNBC.

Biden is also enlisting the Federal Emergency Management Agency to provide the kind of centralized coordination that has been missing. FEMA is supposed to work with the National Guard, states, and localities to support existing community vaccination centers, or set up new ones, including equipping and staffing the sites.

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Biden’s proposed $1.9 trillion “American rescue plan” includes $160 billion to create national vaccination and testing programs. The $900 billion COVID-19 relief package passed by Congress in December also includes funds to accelerate vaccine distribution.

Michael Mina, an epidemiologist and diagnostic testing expert at Harvard’s Chan School of Public Health, said that conceptually, setting up mass federally supported vaccination sites should improve efficiency. “I do think that will likely be a benefit vs. asking everyone to reinvent the wheel,” he said Friday.

Claire Hannan, executive director of the Association of Immunization Managers, told Kaiser Health News that Biden has introduced two things that are key to improving vaccine distribution: a strong vision and clear communication.

She said the goal of 100 million shots in 100 days is “attainable,” but “extremely challenging.”

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That was echoed by Michael Osterholm, a University of Minnesota infectious disease researcher and a member of Biden’s COVID-19 task force, who called the goal “aspirational but doable.”

“The first days of that 100 days may be substantially slower than it will be toward the end,” Osterholm told STAT News. “It’s not going to occur quickly. You’re going to see the ramp-up occurring only when the resources really begin to flow.”

In contrast, Paul Offit, a pediatrician and vaccine expert at Children’s Hospital of Philadelphia, sees the goal as too modest.

“I love that he set a goal, but a million doses a day?” Offit told the New York Times. “We can do better. We are going to have to if we really want to get on top of this virus by, say, summer.”

Staff reporter Tom Avril contributed to this article.