President Biden, facing a slowing rate of vaccinations and a hope for near normalcy by Independence Day, said the government would shift from mass vaccination sites to local settings.WASHINGTON — President Biden, confronting lagging vaccinations that threaten his promise of near normalcy by July 4, on Tuesday overhauled the strategy to battle the pandemic, shifting from mass vaccination sites to more local settings to target younger Americans and those hesitant to get a shot.In a speech at the White House, Mr. Biden said he was launching a new phase in the fight against the coronavirus, with a goal of at least partly vaccinating 70 percent of adults by Independence Day and with a personal plea to all of the unvaccinated: “This is your choice. It’s life and death.”After three months of battling supply shortages and distribution bottlenecks, the Biden administration is confronting a problem that the president said was inevitable: Many of those who were most eager to get vaccinated have already done so. Vaccination sites at stadiums once filled with carloads of people seeking shots are closing, and states that once clamored for more vaccines are finding that they cannot use all of the doses that the federal government wants to ship to them.Yet the administration’s own health experts say tens of millions more Americans must be vaccinated before the infection rate is low enough to return to what many people consider ordinary life.The administration now wants tens of thousands of pharmacies to allow people to walk in for shots. It has also ordered up pop-up and mobile clinics, especially in rural areas, and it plans to devote tens of millions of dollars for community outreach workers to provide transport and help arrange child care for those in high-risk neighborhoods who want to be vaccinated.To build up confidence in vaccines, federal officials plan to enlist the help of family doctors and other emissaries who are trusted voices in their communities.In a new effort to match supply with demand, federal officials informed states on Tuesday that if they did not order their full allocation of doses in any given week, that vaccine would be considered part of a federal pool that is available to other states that want to order more. Until now, if states failed to order all of the doses allotted to them on the basis of population, they could carry over that supply to the next week.Mr. Biden also announced a new federal website and phone number that will help people find the vaccination site closest to them. “We’re going to make it easier than ever to get vaccinated,” he promised.The administration is hoping for an uptick in vaccinations if the Food and Drug Administration authorizes the use of the Pfizer-BioNTech vaccine for adolescents ages 12 to 15 by early next week, as expected. The president said adolescents were important in the fight against the virus because while they are not as susceptible to severe disease, they can still get sick and infect others.Experts say the United States may never reach herd immunity, the point at which the virus dies out because of a lack of hosts to transmit it. And the president suggested that the nation was still far from beating the pandemic.While the vast majority of seniors have been vaccinated, “We’re still losing hundreds of Americans under 65 years of age every week,” Mr. Biden said. “And many more are getting seriously ill from long stretches at a time.” He warned that the nation would be vaccinating people into the fall.Still, the president said, if 70 percent of the nation’s adults have received at least one shot of vaccine by July 4, “Americans will have taken a serious step toward a return to normal.”To get there, Mr. Biden said, the government must shift the focus from mass vaccination sites to doctors’ offices, pharmacies and other local settings, and mount a far more concerted effort to reach those who are reluctant to get shots or simply figure it is too much trouble.“We’re going to keep at it,” the president said, expressing optimism that “most people will be convinced by the fact that their failure to get the vaccine may cause other people to get sick and maybe die.”As of Tuesday, more than 106 million people in the United States were fully vaccinated and more than 56 percent of adults — or almost 148 million people — had received at least one shot. That has contributed to a steep decline in infections, hospitalizations and deaths across all age groups, federal officials said.But despite a flood of doses available, the pace of vaccination has fallen off considerably over the past two and a half weeks. Providers are now administering an average of about 2.19 million doses per day, about a 35 percent decrease from the peak of 3.38 million reported on April 13, according to data from the Centers for Disease Control and Prevention.Mr. Biden called for 160 million adults to be fully vaccinated by July 4 — an increase of 55 million people, or more than 50 percent. About 35 million more adults would have to receive at least one shot to reach the president’s goal of 70 percent of adults who are at least partly protected. While this next phase of the vaccination effort is “easier because I don’t have to put together this massive logistical effort,” Mr. Biden said, “in the other sense it’s harder, it’s beyond my personal control.”Asked whether the United States would help other countries that are worse off, the president promised that by the Fourth of July, his administration will “have sent about 10 percent of what we have to other nations.” It was not clear whether he was referring only to doses from AstraZeneca, which is not authorized for distribution in the United States, or to the nation’s vaccine stock as a whole. He also pledged to move quickly “to get as many doses from Moderna and Pfizer as possibly can be produced and export those around the world.”Until now, White House officials have stuck to formulas that allocated vaccine doses to the states by population, and they were extremely reluctant to send doses of approved vaccines abroad. The administration had been unwilling to shift doses to states that were faster to administer them out of a concern that rural areas or underserved communities would lose out to urban or richer areas where residents were more willing to get shots.But as the pace of vaccination slows, officials have decided that the benefits of a looser system outweigh that risk.States that want more than their allotment will be able to request up to 50 percent more doses, officials said. States that do not claim all of their doses one week will not be penalized and will still be able to request their full allotments the next week, officials said.A vaccination site in April at a church in Queens.James Estrin/The New York TimesThe shift makes little difference to some states that have routinely drawn down as many doses as the federal government was willing to ship. But it could help some states that are able to use more than the federal government was shipping.Jen Psaki, the White House press secretary, said on Tuesday that the move offered governors more flexibility. “Even just a few weeks ago,” she said, “we were in a different phase of our vaccination effort when supply was more constrained, and states for the most part were ordering at or near their full allocation.”Virginia is a case in point. Last week, for the first time, the state did not order every dose it could have, said Dr. Danny Avula, the state vaccine coordinator.Now, he said, “supply is exceeding demand across the state, and the work will be much slower and harder as we find ways to vaccinate a few people at a time.” Dr. Avula said the change “will be very helpful for the handful of states that still have localized areas with high demand.”States with low demand, like Arkansas, may find that their allotted doses are being shipped elsewhere. Arkansas has used only 69 percent of the doses delivered to it so far, data shows. Last week, a state health department spokeswoman said, the state did not order any doses from the federal government. Just over a third of adults in Arkansas have received at least one dose, one of the lowest totals in the country.See How the Vaccine Rollout Is Going in Your County and StateSee where doses have gone, and who is eligible for a shot in each state.Ms. Psaki said the administration was working with states to determine what kinds of settings made the most sense at this point in the vaccination campaign.“We’re constantly evaluating the best delivery mechanisms,” she said, “and if something is not the most effective one, we will make changes.”Mr. Biden suggested that family doctors and pediatricians will play a key role in propelling the vaccination program, as will other community figures. If the Pfizer vaccine is authorized for adolescents, he said, the administration plans to immediately make it available to them at about 20,000 pharmacies that participate in the federal vaccination program.But some doses will be shipped directly to pediatricians so that “parents and their children can talk to their family doctor about it and get the shot from a provider they trust the most,” the president said. Dr. Vivek Murthy, the surgeon general, said last week that about “80 percent of people who are trying to decide about a vaccine say that they want to talk to their doctor about that decision — and we’ve heard that loud and clear.”

A manufacturing subcontractor in Baltimore mixed ingredients from the coronavirus vaccines of Johnson & Johnson and AstraZeneca, setting back U.S. production of the “one-and-done” shot.WASHINGTON — Workers at a plant in Baltimore manufacturing two coronavirus vaccines accidentally conflated the ingredients several weeks ago, contaminating as many as 15 million doses of Johnson & Johnson’s vaccine and forcing regulators to delay authorization of the plant’s production lines.The plant is run by Emergent BioSolutions, a manufacturing partner to both Johnson & Johnson and AstraZeneca, the British-Swedish company whose vaccine has yet to be authorized for use in the United States. Federal officials attributed the mistake to human error.The mix-up has delayed future shipments of Johnson & Johnson doses in the United States while the Food and Drug Administration investigates what occurred. Johnson & Johnson has moved to strengthen its control over Emergent BioSolutions’ work to avoid additional quality lapses.The mistake is a major embarrassment both for Johnson & Johnson, whose one-dose vaccine has been credited with speeding up the national immunization program, and for Emergent, its subcontractor, which has faced fierce criticism for its heavy lobbying for federal contracts, especially for the government’s emergency health stockpile.The error does not affect any Johnson & Johnson doses that are currently being delivered and used nationwide, including the shipments that states are counting on next week. All those doses were produced in the Netherlands, where operations have been fully approved by federal regulators.Further shipments of the Johnson & Johnson vaccine — projected to total tens of millions of doses in the next month — were supposed to come from the giant plant in Baltimore. Those deliveries are now in question while the quality control issues are sorted out, according to people familiar with the matter.Federal officials still expect to have enough doses from the three approved coronavirus vaccine makers to meet President Biden’s commitment to provide enough vaccine to immunize every adult by the end of May. The two other federally authorized manufacturers, Pfizer-BioNTech and Moderna, are continuing to deliver as expected.Pfizer is shipping its doses ahead of schedule, and Moderna is on the verge of winning approval to deliver vials of vaccine packed with up to 15 doses instead of 10, further bolstering the nation’s stock.The problems arose in a new plant that the federal government enlisted last year to produce both Johnson & Johnson’s and AstraZeneca’s vaccines. Both use similar technology in which genes unique to the coronavirus are shuttled into human cells, where they cause the immune system to produce antibodies.In less than a year, Emergent hired and trained hundreds of new workers to produce millions of doses of both vaccines that were supposed to be ready by the time that clinical trials showed whether they actually worked. In late February, one or more workers somehow confused a key ingredient for AstraZeneca’s vaccine with Johnson & Johnson’s, raising questions about training and supervision.Vaccine production is a notoriously fickle science, and errors are often expected to occur and ruin batches. But Emergent’s mistake went undiscovered for days until Johnson & Johnson’s quality control checks uncovered it, according to people familiar with the situation. By then, up to 15 million doses had been contaminated, the people said.None of the doses ever left the plant, and the lot has been quarantined. There is no indication that production of AstraZeneca’s vaccine, which has yet to be authorized for emergency use by the Food and Drug Administration, was affected.Johnson & Johnson reported the mishap to federal regulators, who then started an investigation that has delayed the authorization of that plant’s production lines. The company has beefed up the number of its own staff members who monitor Emergent’s work and instituted a variety of new checks intended to protect against future lapses.Johnson & Johnson already faced a lag in its manufacturing that has caused the company to fall behind on its commitments to the federal government, but it seemed on track to catch up. It delivered 20 million doses by the end of March, and has pledged to deliver about another roughly 75 million by the million doses by the end of May.White House officials hedged their projections in a phone call with governors on Tuesday, forecasting certain deliveries from Pfizer and Moderna but warning that Johnson & Johnson’s shipments would fluctuate.In a statement late Wednesday, the company said it expected the steps it was now taking with Emergent would enable it to deliver 24 million doses by the end of April, or about what the federal government expected. But that depends on whether Johnson & Johnson satisfies Food and Drug Administration regulators.The agency last week cleared a bottling facility that Johnson & Johnson uses in Indiana, allowing the release of more doses made in the Netherlands. But that facility cannot send out doses produced in the Emergent plant until the Food and Drug Administration authorizes it.Nearly seven million doses of the vaccine have been delivered so far, and about half of those have been administered, according to the Centers for Disease Control and Prevention.

As U.S. manufacturers hit their stride, vaccine scarcity will soon turn to plenty as much of the world goes begging. And vaccine makers need answers now about what to do with the coming surplus.WASHINGTON — Biden administration officials are anticipating the supply of coronavirus vaccine to outstrip U.S. demand by mid-May if not sooner, and are grappling with what to do with looming surpluses when vaccine scarcity turns to glut.President Biden has promised enough doses by the end of May to immunize all of the nation’s roughly 260 million adults who are eligible for shots. But between then and the end of July, the government has locked in commitments from manufacturers for enough vaccine to cover another 100 million people — or about 70 million more than the nation’s entire population.Whether to keep, modify or redirect those orders is a question with significant implications, not just for the nation’s efforts to contain the virus but also for how soon the pandemic can be brought to an end. Of the vaccine doses given globally, about three-quarters have gone to only 10 countries. At least 30 countries have not yet injected a single person.And global scarcity threatens to grow more acute as nations and regions clamp down on vaccine exports. With infections soaring, India, which had been a major vaccine distributor, is now holding back nearly all of the 2.4 million doses manufactured daily by a private company there. That action follows the European Union’s decision this week to move emergency legislation that would curb vaccine exports for the next six weeks.Biden administration officials who are inclined to hold on to the coming U.S. surplus point to unmet need and rising uncertainty: Children and adolescents are still unvaccinated, and no one is certain if or when immunity could wear off, which could require scores of millions of booster shots.“We want to, largely, be a part of the global solution here,” Jen Psaki, the White House press secretary, said this week. But she added, “There are still a number of factors that are unpredictable that we need to plan for to the best of our ability, including the variants and the impact and what will be most effective, as well as what will work best with children.”Vaccine manufacturers and some top federal officials say decisions about what to do with extra orders must be made within weeks, or the uncertainty could slow production lines. The manufacturing process can take up to 10 weeks, and changes for a foreign market need time. The regulatory rules that govern vaccine shipments present another hurdle, as does the limited storage life of the drug substances that make the vaccine.Vials in the nation’s bottling plants in Michigan and Indiana are being labeled for use at home. If their destination is unclear, either the production line must pause or vials directed for overseas may need to be relabeled.Once the doses are shipped out to states, federal regulations prohibit recalling them even if they are not needed domestically. And vials cannot sit in storage forever: While vaccine itself can last up to a year in a frozen state, once bottled it must be used within four to six months.All these variables threaten to complicate what so far has been relatively smooth sailing for the Biden administration. Thanks in part to the federal government’s determined assistance over many months, vaccine manufacturers have been steadily increasing their output, and states have snapped up new doses as fast as the government could deliver them.Where to go from here is a matter of intense debate.Clinical trials to determine which vaccines work for the nation’s adolescents and children are continuing and most likely will not neatly wind up at the same time. By the end of spring, for example, Moderna and Pfizer are hoping for interim results on how their vaccines would work for the nation’s 30-some-million adolescents. But Moderna, at least, does not expect results for children under 12 until after the school year starts next fall.The administration could hang on to doses from those two manufacturers while it awaits findings, only to discover later that another vaccine whose trials began later — say Johnson & Johnson’s — is a better option.If one or more of the three authorized vaccines turn out to provide only brief protection against Covid-19, scores of millions of more doses could be required for booster shots. But when that answer will come is also uncertain.A woman received one of New Jersey’s first Johnson & Johnson vaccine doses this month. Of all the vaccine doses given globally, about three-quarters have gone to only 10 countries.Bryan Anselm for The New York TimesFederal health officials have also discussed canceling or reducing some orders from Moderna and Pfizer in return for the promise of a fresh supply this fall of either pediatric doses or shots of a new vaccine that has been reconfigured to work against the fast-spreading variants.There is some push for that from the manufacturers, whose vaccines are coveted by other high-income countries. But it would also deprive federal officials of the power to decide which nations get the surplus doses, as well as the humanitarian and diplomatic credit it would reap from sending the vaccine to countries in greater need.For all these reasons, senior officials say, the administration is leaning toward keeping the doses it has ordered then at some point directing the excess to other nations in bilateral deals or giving it to Covax, an international nonprofit organization backed by the World Health Organization that is trying to coordinate equitable distribution of vaccine. The Biden administration has already donated $4 billion to that international effort.Mr. Biden has stressed that his top priority is to protect Americans, but pressure is growing to share the U.S. stock. The United States has ordered a billion doses from the three federally authorized manufacturers and AstraZeneca, whose vaccine is not yet cleared for emergency use in the States but has been authorized by more than 70 countries. It recently announced that it was negotiating a deal with Johnson & Johnson for enough doses to cover another 100 million.Taken together, the supply would be enough to vaccinate 650 million people — nearly twice the U.S. population. With the world’s highest death toll from Covid-19, the United States has fully vaccinated 14 percent of its population.Last week, the White House announced that it would share four million doses of AstraZeneca’s vaccine with Mexico and Canada, but emphasized that no Americans would lose out because the vaccine has not been deployed here yet.That is a trickle compared with the 300 million AstraZeneca doses the federal government has ordered, enough to cover 150 million people with the two-dose regimen. Senior administration officials say tens of millions of those doses can be released now or imminently, and tens of millions of unbottled doses possibly could also be given away.Brazil is particularly eager for help. With more than 300,000 lives lost, the country has the second-highest death toll and has fully vaccinated less than 2 percent of its population.“After we do take care of the really difficult situation we’ve had in our own country with over 535,000 deaths, we will obviously, in the future, have surplus vaccine, and there certainly is a consideration for making that vaccine available to countries that need it,” Dr. Anthony S. Fauci, the government’s top infectious disease expert, said at a White House news conference on Wednesday.He has cast early May, when the Biden administration wants states to open up vaccinations to all adults, as a turning point. In an interview this week, he said it was likely that anyone who wants a vaccine would be able get one then.Some will not want to be vaccinated, although their numbers appear to be dwindling. According to a Pew Research Center poll this month, 69 percent of the public intends to get inoculated or already has.In the summer, the U.S. production outlook brightens further. Pfizer and Moderna together have promised enough doses to cover another 100 million people by the end of July.Pfizer continues to beef up its production lines. And Moderna is hoping to win regulatory approval to increase the number of doses in each vial by at least 40 percent, although shortages of specialized syringes might hinder that plan.A shipment of the AstraZeneca vaccine arriving in Ethiopia this month, as part of the United Nations-led Covax program.Amanuel Sileshi/Agence France-Presse — Getty ImagesJohnson & Johnson has been slower to scale up its manufacturing in the United States and is now racing to deliver as many as 24 million doses manufactured at its Dutch plant by the end of the month, according to federal officials. The Food and Drug Administration just certified its new bottling operation in Indiana and is expected any day to approve its vaccine production lines at a Baltimore plant.But while Johnson & Johnson has lagged behind the other manufacturers, its technology carries enormous promise for mass production because it can deliver many more doses per lot.Later this year, when Merck & Company is expected to begin producing Johnson & Johnson’s vaccine, it could churn out 100 million doses a month — or as much as Pfizer and Moderna together deliver monthly. The White House hailed the deal between Johnson & Johnson and Merck, but by the time production gets up to speed, those doses may be bound for a growing surplus or for export.One option is to ship the frozen vaccine that will be manufactured in Merck’s plant overseas, where it can be bottled much more cheaply. Of the $10 that the federal government has agreed to pay for a dose of Johnson & Johnson’s vaccine, the drug substance itself accounts for only about 30 cents, federal officials said. The rest is the so-called fill-and-finish cost.If AstraZeneca wins emergency use authorization from U.S. regulators, that will throw still more shots into the mix. Officials expect about 50 million doses to be ready for delivery in May.But Biden administration officials are skittish about AstraZeneca’s vaccine. It appears to be roughly as effective as Johnson & Johnson’s but requires an additional shot, meaning a more complicated rollout. Some health officials worry that if there are already enough doses in the pipeline to cover every adult who wants a shot, introducing a fourth vaccine will just confuse people.On the other hand, if the administration decides to donate the AstraZeneca doses without offering any to its own citizens, other countries might conclude that the United States lacks confidence in the vaccine’s safety or effectiveness.“As we gain more confidence in the doses that we have and the ability or the need or not to be boosting, then we can make a more definitive statement about what the role of the AZ product is going to be in the United States” should it gain clearance, Dr. Fauci said in an interview this week, “but right now I think it’s too premature to say anything.”Sheryl Gay Stolberg