‘Have At It,’ Biden Says to G.O.P. Who Have Threatened Vaccine Mandate Challenges

The U.S. Food and Drug Administration is “working around the clock” to make Covid vaccines available to young children, it said in a statement on Friday. In the meantime, however, the agency urged parents not to seek out the shots for children who are under 12, and therefore not yet eligible for vaccination.

The agency said that it hoped vaccines would be available for young children “in the coming months,” but that it could not offer a more specific timeline. However, once it has applications from the vaccine manufacturers in hand, it will “be prepared to complete its review as quickly as possible, likely in a matter of weeks rather than months,” Dr. Janet Woodcock, the acting F.D.A. commissioner, and Dr. Peter Marks, of the agency’s Center for Biologics Research and Evaluation, said in the statement.

The available vaccines, none of which have been cleared for children under 12, may not be a safe or effective dose for young children, the agency noted. Pediatric clinical trials, which will help determine the right vaccine dose for children under 12, are still underway.

“Children are not small adults — and issues that may be addressed in pediatric vaccine trials can include whether there is a need for different doses or different strength formulations of vaccines already used for adults,” Dr. Woodcock and Dr. Marks.

Health officials have previously expressed concern that full approval of the Pfizer-BioNTech vaccine for people 16 and up might prompt parents to seek, or doctors to give, the shots off-label to young children, specifically warning against the move. Children younger than 12 make up a sizable unvaccinated population in the United States.

Some vaccine manufacturers are still enrolling children in their trials and others are still giving the shots and monitoring children for potential side effects, the F.D.A. noted in its statement. The trials will follow participants for at least two months to ensure that the researchers are able to detect any adverse events. Vaccine manufacturers then have to analyze the data and then formally apply for authorization or approval from the F.D.A.

Then, the agency “will carefully, thoroughly and independently examine the data to evaluate benefits and risks,” Dr. Woodcock and Dr. Marks said.

They added, “Just like every vaccine decision we’ve made during this pandemic, our evaluation of data on the use of Covid-19 vaccines in children will not cut any corners.”

In an interview published on Friday, Ozlem Tureci, the co-founder of BioNTech and its chief medical officer, told Der Spiegel, a German news site, that “we will be presenting the results from our study on five- to 11-year-olds to authorities around the world in the coming weeks.”

Initially reluctant to enact mandates, President Biden is now moving more aggressively than any other president in modern history to require vaccination, including in schools.

The president traveled to Brookland Middle School in Washington on Friday with Jill Biden, the first lady, a college professor who returned to the classroom this week. In his remarks, Mr. Biden urged parents to get eligible children vaccinated, and promised a White House visit to the school once every student received a vaccine.

“The safest thing you can do for your child 12 and older is get them vaccinated,” the president told the crowd. “You’ve got them vaccinated for all kinds of other things — measles mumps rubella — for them to go to school, to be able to play sports, they’ve had to have these vaccinations. Get them vaccinated.”

A slate of new requirements announced this week would apply to those who teach in Head Start programs, Department of Defense Schools, and schools operated by the Bureau of Indian Education. Collectively, those schools serve more than 1 million children and employ nearly 300,000 staff, according to the plan released by administration officials.

“We cannot always know what the future holds, but we do know what we owe our children,” Dr. Biden said on Friday. “We owe them a promise to keep their schools open as safe as possible. We owe them a commitment to follow the science.”

The surge of new cases, driven by the more contagious Delta variant, ripping through unvaccinated communities has also impacted children, who are currently being hospitalized at the highest levels reported to date, with nearly 30,000 entering hospitals in August.

Children still remain markedly less likely to be hospitalized or die from Covid-19 than adults, especially older adults. But experts say that the growing number of hospitalized children, however small compared with adults, should not be an afterthought, and should instead encourage communities to work harder to protect their youngest residents.

Christopher F. Schuetze contributed reporting.

Florida’s ban on school mask mandates can remain in place while a legal challenge makes its way through the courts, an appeals court ruled on Friday. It reverses the decision of a lower court judge who had put the ban on hold and allowed the state’s largest school districts to require face coverings amid a deadly coronavirus surge.

The ruling in favor of Gov. Ron DeSantis, a Republican, and other state officials by the First District Court of Appeal in Tallahassee means the Florida Department of Education can continue to punish local school officials who impose mask mandates without an opt-out provision available for parents. The Centers for Disease Control and Prevention has advised everyone in schools to wear masks, regardless of vaccination status.

“In the trial courts in Tallahassee, state and federal, we typically lose if there’s a political component to it, but then in the appeals court, we almost always win,” Mr. DeSantis said on Wednesday.

The state has begun to withhold funds equivalent to the school board members’ monthly salaries from two districts — Alachua in Gainesville and Broward in Fort Lauderdale — that were the first to put strict mask mandates in place. In all, 13 of Florida’s 67 districts have imposed similar mandates, in defiance of the state.

Florida’s hardline stance on mask mandates has drawn a response from the U.S. Department of Education’s civil rights office, which announced Friday it was investigating whether Florida was preventing schools from meeting the needs of students with disabilities. The office was already investigating five other states with mask mandate bans.

The investigations make good on the Biden administration’s promise to use the federal government’s muscle — including civil rights investigations and legal action — to intervene in states where governors and other policymakers have come out against mask mandates in public schools. The C.D.C. recommends that everyone in schools wear masks, regardless of vaccination status.

The Biden administration has pledged to restore funding to any district that is penalized for implementing C.D.C. mitigation recommendations, such as universal masking. The federal Education Department has already informed districts that they can use federal relief funds to plug gaps, and announced Thursday a new grant program that would provide an additional pot of funding to make districts whole if they’re financially penalized.

In a brief ruling, three judges on the more conservative appellate court wrote on Friday that they have “serious doubts” about basic matters in the case, including whether the parents who filed the initial lawsuit had legal standing to do so.

“These doubts significantly militate against the likelihood of the appellees’ ultimate success in this appeal,” they wrote.

Late last month, after a four-day trial, Judge John C. Cooper of the state’s Second Judicial Circuit had ruled in favor of the parents, saying that school districts’ mask mandates were narrow, reasonable and necessary to protect a compelling state interest — namely, the safety of students and staff. The state immediately sought a stay, or hold, on the ruling, pending its appeal.

On Wednesday, Judge Cooper rejected the stay, briefly allowing the mask mandates to remain in place until Friday’s appellate court ruling.

Erica L. Green contributed reporting.

A day after President Biden issued broad vaccine mandates aimed at propelling American workers to get vaccinated against the coronavirus, federal health officials released a handful of studies highlighting how effective the shots are at preventing infections, hospitalizations and deaths — even while the highly contagious Delta variant has been dominant.

Three studies that drew data from different U.S. regions evaluated the protective power of the vaccines. One looked at more than 600,000 virus cases in 13 states, representing about one quarter of the U.S. population, between April and July, and concluded that individuals who were not fully vaccinated were far more susceptible to infection and death from the virus.

They were 4.5 times more likely than vaccinated individuals to become infected, 10 times more likely to be hospitalized, and 11 times more likely to die from the coronavirus, the study found.

Vaccine protection against hospitalization and death remained strong even when the Delta variant was the dominant form of infection. But the vaccines’ effectiveness in preventing infection dropped from 91 percent to 78 percent, the study found.

The studies underscore a series of similar findings in recent weeks.

“As we have shown, study after study, vaccination works,” said Dr. Rochelle Walensky, the director of the Centers for Disease Control and Prevention, at a White House Covid briefing on Friday.

As more and more Americans become vaccinated, experts always expected that immunized people would represent a greater percentage of hospitalized patients. “What I want to reiterate here is it’s still well over 90 percent of people who are in the hospital who are unvaccinated,” Dr. Walensky said.

“We still have more than 10 times the number of people in the hospital who are unvaccinated, compared to vaccinated,” she added.

The unvaccinated are not a monolith. They include people who were opposed to vaccines even before the coronavirus pandemic, a group that consumes misinformation on the internet falsely claiming that vaccines commonly cause dangerous side effects and injuries. There are also unvaccinated Americans who have little access to health care, who have not seen a doctor in years and are disconnected from the medical establishment — or who are simply afraid of needles.

Some have religious objections, or are concerned that the vaccines were developed too quickly, though they are the culmination of decades of scientific research. Others have already had Covid and believe that they have immunity that makes a vaccine unnecessary, although the C.D.C. urges previously infected people to get vaccinated because natural immunity may not be enough to prevent reinfection. And millions of unvaccinated Americans have no choice in the matter: They are under 12 years old and are still waiting for a vaccine to be cleared for their use.

Two other studies published on Friday detected waning protection from the vaccines among older adults.

One study, conducted at five Veterans Affairs Medical Centers, found that protection against hospitalization declined with age, to 80 percent for those aged 66 and older, down from 95 percent for adults aged 18 to 64. A second study found vaccine effectiveness dropped off at age 75.

The findings could help identify populations who may be in need of additional doses or booster shots. In August, the Food and Drug Administration authorized giving third doses of Pfizer-BioNTech’s and Moderna’s coronavirus vaccines for some people with weakened immune systems, including organ transplant patients.

But officials have said there is insufficient data on whether the vaccines’ effectiveness declines over time to recommend boosters for healthy adults.

The data also suggests that the Moderna vaccine may be slightly more effective at preventing infections and hospitalizations with the Delta variant, compared with the Pfizer-BioNTech vaccine. Both of the mRNA vaccines had higher efficacy rates than the Johnson & Johnson shot, but the studies were not originally designed to evaluate the comparative effectiveness of different vaccinations.

In the study of 33,000 medical encounters in nine states between June and August, the Moderna vaccine had an effectiveness rate of 92 percent against infection, compared with 77 percent for the Pfizer-BioNTech shot.

Sharon LaFraniere and Julie Bosman contributed reporting.

President Biden’s new coronavirus vaccine mandates will have sweeping ramifications for businesses, schools and the political discourse in the United States. But for many scientists, the question is a simpler one: Will these measures turn back a surging pandemic?

The answer: Yes, in the longer term.

It has become clear that the nation cannot hope to end the pandemic with some 37 percent of Americans not having received a single dose of Covid vaccine, several experts said in interviews. Cases and hospitalizations are only expected to rise as Americans move indoors in homes, schools and offices in the cooling weather.

The administration’s new plan should stem the flood of infections and return the country to some semblance of normalcy over the longer term, the researchers said.

“It’s going to fundamentally shift the arc of the current surge,” said Dr. Ashish Jha, dean of Brown University School of Public Health. “It’s exactly what’s needed at this moment.”

The vaccine mandates will protect millions more people, particularly against severe disease, and relieve pressure on the health care system, said Natalie Dean, a biostatistician at Emory University. “It also sets a precedent for other organizations to make similar decisions” about mandates, she said.

But some experts cautioned that the results from the aggressive plan would take many weeks to unfold. Immunization is not an instant process — at least six weeks for a two-dose vaccine — and the administration did not emphasize the measures that work more quickly: masking and widespread rapid testing, for example.

The nation has been overtaken by the contagious Delta variant, a far more formidable foe than the original version of the virus. The optimism of the spring and early summer gave way to dread as experts observed the variant’s march across Asia and Europe, sending rates soaring even in Britain, which had successfully protected most of its older adults.

The variant became the dominant version of the virus in the United States only in mid-July, and the consequences have been beyond anything experts predicted. Reassuringly low numbers of cases and hospitalizations in June have risen inexorably for weeks to nearly 10-fold their levels. About 1,500 Americans, the vast majority of them unvaccinated, are dying each day.

The mandates arrived on Thursday after weeks of arguments from public health experts that the federal government must do much more to raise vaccination rates.

The administration’s mandates will affect nearly 100 million Americans. Among them are health care workers. The administration will require that any provider receiving Medicaid or Medicare funding impose a vaccination requirement on staff.

This is the measure mostly likely to have an immediate impact, experts said, because health care facilities are high-risk settings for transmission. And there is ample historical precedent for the decision to hold hospitals to certain standards — notably, the historical directive to desegregate patients by race, said Dr. Jha.

“We have a real dearth of leadership from health care systems that have not mandated within their own organizations, and it is imperative that the president require that patients be protected,” he added.

The requirement may drive some health care and nursing home workers, particularly many who are close to retirement age, to leave the profession. Even so, there is more to be gained than lost by the mandates, said Dr. Nahid Bhadelia, founding director of Boston University’s Center for Emerging Infectious Diseases Policy and Research.

“This is an important step to get us out of the pandemic,” she said. “The very people who are taking care of the vulnerable coming into the hospital need to be our first line of defense.”

The Labor Department will require all private-sector businesses with more than 100 employees to require that their workforces be fully vaccinated or be tested at least once a week. Employers will be required to give paid time off to employees to get vaccinated.

That move alone will affect 80 million Americans; it’s not clear how many are already vaccinated. In any event, the effects will not be immediately evident.

Given the time required between the first two doses of the vaccine, and then for immunity to build up, the effect of all these mandates is unlikely to be felt for many weeks, said Bill Hanage, an epidemiologist at Harvard University.

And Dr. Hanage was skeptical that the mandates would be successful in inoculating millions more people than have already opted for the vaccine. Some of the people who most urgently need to be protected are older adults who will not be affected by workplace requirements.

“I’m sure that the anti-vaxxers are already prepared to be up in arms about this,” he said. (Republican governors in several states have decried the mandates as unconstitutional and say they plan to file suits to stop them.)

By insisting that vaccination is the way out of the pandemic, officials in both the Trump and Biden administrations have de-emphasized the importance of masks and testing in controlling the pandemic, several experts said.

“It’s a lot quicker to put on a mask than it is to get a bunch of people vaccinated,” Dr. Hanage said.

Republican governors across the country assailed President Biden’s aggressive moves to require vaccinations as an unconstitutional attack on personal freedoms and vowed to sue the administration to block the requirements.

The vaccine mandates Mr. Biden announced on Thursday, affecting tens of millions of private sector employees, health care workers, federal contractors and most federal workers, quickly escalated a political battle between the administration and Republican governors who have spent months fighting against mask rules and other pandemic restrictions even as infections and deaths surged in their states this summer.

Now, they are arguing that Mr. Biden’s plan is a big-government attack on states’ rights, private business and personal choice, and promise swift legal action to challenge it, setting up a high-stakes constitutional showdown over the president’s powers to curb the pandemic.

“@JoeBiden see you in court,” Gov. Kristi Noem of South Dakota wrote on Twitter. Gov. Mark Gordon of Wyoming said the new rule “has no place in America,” and said he had asked the state’s attorney general to be ready to take legal action.

In Texas, Attorney General Ken Paxton questioned President Biden’s authority to require vaccinations or weekly testing at private businesses with more than 100 workers.

“I don’t believe he has the authority to just dictate again from the presidency that every worker in America that works for a large company or a small company has to get a vaccine,” Mr. Paxton said, speaking on a radio show hosted by Steve Bannon, who served as a strategist for Donald J. Trump during part of his presidency. “That is outside the role of the president to dictate.”

Mr. Paxton, a vigorous supporter of the sweeping new antiabortion law in Texas, promised to “fight back” in a message on Twitter: “Not on my watch in Texas.”

Mr. Biden had anticipated the attacks. In announcing his plan on Thursday, he said that he would do what he could to “require more Americans to be vaccinated to combat those blocking public health,” adding “If those governors won’t help us beat the pandemic, I will use my power as president to get them out of the way.”

On Friday, Mr. Biden said that his mandates would withstand Republican challenges.

“Have at it,” said Mr. Biden, who was delivering remarks at a middle school in Washington. “I am so disappointed, particularly that some of the Republican governors have been so cavalier with the health of these kids, so cavalier with the health of their communities.”

Gov. Greg Abbott of Texas called the actions an “assault on private businesses” in a statement on Twitter. He said he issued an executive order protecting Texans’ right to choose whether or not they would be vaccinated. “Texas is already working to halt this power grab,” he wrote.

Gov. Doug Ducey of Arizona wrote on Twitter: “The Biden-Harris administration is hammering down on private businesses and individual freedoms in an unprecedented and dangerous way.” He questioned how many workers would be displaced, businesses fined, and children kept out of the classroom because of the mandates, and he vowed to push back.

Mr. Biden’s vaccination requirements will be imposed by the Department of Labor and its Occupational Safety and Health Administration, which is drafting an emergency temporary standard to carry out the mandate, according to the White House.

OSHA oversees workplace safety, which the agency is likely to contend extends to vaccine mandates. The agency has issued other guidelines for pandemic precautions, such as a rule in June requiring health care employers to provide protective equipment, provide adequate ventilation and ensure social distancing, among other measures.

By requiring that companies maintain safe workplaces through vaccination, legal experts said Friday that the president was relying on the federal government’s well-established constitutional power to regulate commerce and the 51-year-old law establishing the Occupational Safety and Health Administration.

The vaccine requirements drew praise from doctors and scientists who have for months stressed the urgency of increasing vaccination rates to contain the spread of the highly contagious Delta variant, which has raised the national caseload to heights last seen in January, overwhelmed hospitals in hard-hit areas and contributed to the deaths, on average, of more than 1,575 people a day.

However, the nation is so deeply polarized politically that even experts seemed split on how effective Mr. Biden’s plan would be.

Dr. Georges C. Benjamin, executive director of the American Public Health Association, said the actions might be “too little, too late,” and warned that Americans opposed to vaccination might dig in and bristle at being told what to do. The American Hospital Association was cautious, warning of the possibility of “exacerbating the severe work force shortage problems that currently exist.”

But Dr. William Schaffner, an infectious disease expert at Vanderbilt University, likened the vaccination requirements to military service in a time of war.

“To date, we have relied on a volunteer army,” Dr. Schaffner said. “But particularly with the Delta variant, the enemy has been reinforced, and now a volunteer army is not sufficient. We need to institute a draft.”

The unvaccinated, though, are not a monolith. They include people who were opposed to vaccines even before the coronavirus pandemic, a group that consumes misinformation on the internet falsely claiming that vaccines commonly cause dangerous side effects and injuries. There are also unvaccinated Americans who have little access to health care, who have not seen a doctor in years and are disconnected from the medical establishment — or who are simply afraid of needles.

Some have religious objections, or are concerned that the vaccines were developed too quickly, though they are the culmination of decades of scientific research. Others have already had Covid and believe that they have immunity that makes a vaccine unnecessary, although the C.D.C. urges previously infected people to get vaccinated because natural immunity may not be enough to prevent reinfection. And millions of unvaccinated Americans have no choice in the matter: They are under 12 years old and are still waiting for a vaccine to be cleared for their use.

Michael D. Shear and Julie Bosman contributed reporting.

President Biden’s far-reaching assertion of executive authority to require Covid-19 vaccines for 100 million American workers relies on a set of complicated legal tools that will test the power — and the limits — of the federal government to compel personal health care decisions.

To more aggressively confront the coronavirus pandemic, Mr. Biden is pulling several levers of presidential power: He is using an emergency provision in the Occupational Safety and Health Act of 1970; he is threatening to withhold federal funding from hospitals and other health care organizations; and he is embracing his authority as chief executive of the sprawling federal work force and its contractors.

Together, the president’s actions are an assertive use of his jurisdiction over American life as the occupant of the Oval Office. Until Thursday, under Mr. Biden’s leadership, the White House had been far more cautious about mandating vaccines than his counterparts around the world, especially in Europe.

On Friday, facing accusations from Republicans of an abuse of power and threats of lawsuits, Mr. Biden had a simple retort.

“Have at it,” he said.

The right of government to impose vaccines has been established since at least 1904, when the Supreme Court issued a 7-to-2 ruling that Cambridge, Mass., could require all adults to be vaccinated against smallpox. But more recent cases — including the first Supreme Court ruling on the Affordable Care Act — call into question whether Mr. Biden or any president could simply order all Americans to get shots.

That is not what Mr. Biden is doing. By requiring that companies maintain safe workplaces through vaccination, legal experts said Friday that the president was relying on the federal government’s well-established constitutional power to regulate commerce and the 51-year-old law establishing the Occupational Safety and Health Administration.

Once OSHA drafts an “emergency temporary standard,” officials said the agency would begin enforcing the rules: collecting reports of violations and sending out inspectors who will be empowered to impose $13,650 fines for violations and up to $136,500 for those that are willful or repeated.

“The constitutionality of this regulatory effort is completely clear,” said Donald B. Verrilli Jr., who served as solicitor general under President Barack Obama. “In a situation like this, one where we’re in the middle of a public health emergency, courts recognize that they lack the institutional competency to make judgments about what’s in the best interest of public health and safety.”

Mr. Biden’s adversaries are already accusing him of an abuse of power, claiming he has gone too far in confronting a virus that has claimed the lives of more than 600,000 Americans. Senator Ted Cruz, Republican of Texas, called the president’s actions “utterly lawless.” Gov. Brian Kemp, Republican of Georgia, said the move was “blatantly unlawful, and Georgia will not stand for it.”

In a fund-raising email sent on Friday, Gov. Ron DeSantis of Florida, a Republican who has issued antimask orders, wrote, “Joe Biden has declared war on constitutional government, the rule of law, and the jobs and livelihoods of millions of Americans.”

But top aides to the president do not appear to be shaken by what they say was an expected response from those quarters. White House officials believe he has clear authority to compel federal workers to be vaccinated as a condition of their employment by the government. And they say requiring hospitals and other health care organization to vaccinate its workers — a mandate that covers as many as 17 million people — is a reasonable condition in exchange for taking federal health care reimbursements.

Julie Bosman contributed reporting.

President Biden’s far-reaching assertion of presidential authority to require vaccines for 80 million American workers relies on a first-of-its-kind application of a 51-year-old law that grants the federal government the power to protect employees from “grave dangers” at the workplace.

White House officials believe the emergency authority provided by Congress under the Occupational Safety and Health Act of 1970 is a legitimate and legal way to combat the coronavirus pandemic. But they acknowledge that the law’s emergency provisions, which were employed in previous decades to protect workers from asbestos and other industrial dangers, have never been used to require a vaccine.

The novelty of the effort is at the heart of legal threats from Republican lawmakers, governors, pundits and others, many of whom have vowed to challenge the president’s use of the workplace rules. Gov. Brian Kemp, Republican of Georgia, said the move “is blatantly unlawful, and Georgia will not stand for it.” Senator Ted Cruz, Republican of Texas, called Mr. Biden’s actions “utterly lawless” on Twitter.

In a fund-raising email sent on Friday, Gov. Ron DeSantis of Florida, a Republican who has issued antimask orders, wrote, “Joe Biden has declared war on constitutional government, the rule of law, and the jobs and livelihoods of millions of Americans.”

But top aides to the president do not appear to be shaken by what they say was an expected response from those quarters. On Friday morning, Mr. Biden responded to threats of lawsuits from his adversaries.

“Have at it,” he said.

And experts said the administration appeared to be on strong legal ground because it was relying on existing authority granted to the Occupational Safety and Health Administration by the legislative branch and supported by decades of judicial rulings.

President Biden’s new coronavirus vaccination mandates prompted some backlash Thursday, but the two federal departments that already require vaccinations — as well as several states, cities and private-sector companies — say their mandates are already doing what they intended: getting more shots in arms.

Since the Pentagon announced last month that active-duty military personnel would be required to be vaccinated, the percentage of service members with at least one shot rose from 76 percent to 83 percent, according to Defense Department data.

At the Department of Veterans Affairs, which issued a vaccine mandate for its 115,000 frontline health care workers seven weeks ago, 82 percent of those employees are now fully vaccinated, up from 77 percent, and the number of shots it has given to all of its workers has more than doubled since early July, said Terrence Hayes, a spokesman for the department.

The increases elude the goal of getting virtually every employee vaccinated, although in the military, where troops have long been used to taking orders and avoiding voluntary actions, the numbers are expected to rise higher soon. Each service branch is working through its enforcement plan; once the Army makes its official announcement, those numbers are likely to increase, considering it is the largest branch of the military.

Military leaders had grown tired of vaccination rates that had stagnated for months. The low vaccination rate was threatening troop readiness, commanders said, and at the Department of Veterans Affairs, there was fear that vulnerable veterans would be sickened by workers, a concern at nursing homes and private hospitals as well.

GLOBAL ROUNDUP

After a giant Hindu pilgrimage contributed to a catastrophic coronavirus surge this spring, some states in India are preparing for a new season of religious festivals by imposing crowd limits, as experts warn of the threat of a third wave of infections.

Several festivals taking place in September and October typically draw large crowds to temples, processions and markets. In the past, the authorities have struggled to get devotees to follow health protocols. The Kumbh Mela, which drew millions of pilgrims to the banks of the Ganges River in the spring with hardly any testing or social distancing, was widely blamed for spreading the virus, as pilgrims carried infections back to their villages and towns.

Prime Minister Narendra Modi’s Hindu nationalist government faced criticism for allowing the Kumbh Mela to take place despite warnings that it would become a super-spreading event. Last month, Mr. Modi’s government asked states to take “suitable measures to avoid large gatherings during the coming festive season,” and to impose local restrictions if needed.

At a news conference last week, Dr. V.K. Paul, head of the national Covid-19 task force, reinforced the warning, saying: “We shall celebrate the festivals within the family — we should not have big gatherings.”

States have responded with varying measures in the days before a festival celebrating Ganesh, the Hindu elephant god. In the southwestern state of Karnataka, the government said that gatherings should be capped at 20 people, and imposed a 9 p.m. curfew. In the southern state of Tamil Nadu, officials announced a ban on large celebrations, and offered payments to idol-making potters whose businesses would be badly affected.

The western state of Maharashtra, among the worst hit by the spring Covid wave, draws some of the biggest crowds for the festival, known as Ganesh Chaturthi. In Mumbai, the state capital, the authorities issued guidelines limiting processions to 10 people, all of whom must be fully vaccinated and masked, news media reported.

Although India’s outbreak has eased, the country continues to report nearly 40,000 new cases and nearly 400 deaths daily. With Covid fatigue kicking in and the economy still flailing, many states are reluctant to impose strict restrictions. Prime Minister Narendra Modi’s government has bet that a ramped-up vaccination drive can boost immunity and keep another wave from being as deadly as the last.

With localized virus surges taking place in a handful of states, Dr. Lahariya said that continued restrictions could help prevent a nationwide third wave as India’s vaccination rates remain relatively low.

After a slow start to vaccinations, India has administered more than eight million doses per day over the past week. More than 700 million doses have been given nationwide, but less than one-fifth of the country’s roughly 900 million adults are fully vaccinated, according to official statistics.

In other news around the world:

• The French government announced on Thursday that it had granted citizenship to more than 12,000 foreign essential workers to thank them for their service during the pandemic. Data from the Health Observatory of the Île-de-France region, an area that includes Paris, show that immigrants made up a quarter of essential workers who remained active during lockdowns. Of those working in the hospitals in the region, 23 percent are immigrants, though some may already be citizens.

• Singapore opened its borders to more countries and loosened quarantine rules for some inbound travelers on Friday, even though its daily case count on Thursday surged to over 400 for the first time since August 2020. But the number of severe cases has leveled off at an average of 23 per day this week, according to data released by Singapore’s Ministry of Health.

• In Vietnam, officials in Ho Chi Minh City, the epicenter of the country’s outbreak, said they planned to allow economic activity to resume in the city next week. “We cannot resort to quarantine and lockdown measures forever,” Prime Minister Pham Minh Chinh said last week, Reuters reported. “The Covid-19 pandemic is evolving in a complicated and unpredictable manner and may last for a long time.”

As Britain’s vaccine watchdog deliberates whether to introduce a booster program for healthy people vaccinated against the coronavirus, Prof. Sarah Gilbert of Oxford University, who led the development of the AstraZeneca vaccine, said on Thursday that a third dose was unnecessary for most.

Prof. Gilbert said in an interview with The Daily Telegraph that booster shots should be prioritized only for the immunocompromised and elderly, because in most people, the immunity from two doses is holding up. “We need to get vaccines to countries where few of the population have been vaccinated so far,” she said. “We have to do better in this regard. The first dose has the most impact.”

The comments came as Britain’s medicine regulator recommended on Wednesday that both the Pfizer and AstraZeneca vaccines could be used as “safe and effective” booster doses.

The regulator’s chief executive, Dr. June Raine, said in a statement that it would now be up to Britain’s vaccines watchdog, the Joint Committee on Vaccination and Immunization, “to advise on whether booster jabs will be given and if so, which vaccines should be used.”

Britain’s health secretary, Sajid Javid, announced this month that a third vaccine dose would be offered to those with severely compromised immune systems, aged 12 and over. The vaccination committee is deliberating whether to roll out boosters more widely, ahead of a winter season that may bring a rise in the number of coronavirus cases.

Several countries have already begun giving booster shots to healthy vaccinated people, or will start this month. But ethical questions about vaccine inequalities have been raised, as these programs are limited to wealthier nations.

The World Health Organization asked wealthy countries to hold off on administering booster shots for healthy patients until at least the end of the year as a way of enabling every country to vaccinate at least 40 percent of their populations.

On Monday, as New York City students fully return to public schools, the city’s entire municipal labor force, the largest in the nation, will return to work.

Mayor Bill de Blasio has ordered the city’s more than 300,000 employees to report to work five days a week, with no general hybrid or remote option. The move will be closely watched in cities around the nation, as the mayor navigates a thicket of safety procedures.

Office workers will have to be vaccinated or submit to weekly testing, and masks will be required in most indoor communal settings. Social distancing will not be required, except where workers are interacting with the public.

The move has been met by significant resistance from unionized workers. But Mr. de Blasio has been determined to restore the city to some semblance of its prepandemic existence, and he believes that returning to work will greatly help efforts to revive the city’s economy.

The New York Times interviewed roughly a dozen city employees, and all but one disapproved of the mayor’s plan. Many worried about working in cramped, open work spaces with unvaccinated colleagues; others wondered how they would balance their child-care responsibilities, should their children have to quarantine following an in-school exposure. Several workers interviewed, who sought anonymity because they were not authorized to speak publicly, said that they or their colleagues would be likely to start looking for other jobs with more flexible work-from-home policies.

“To me, this is crazy,” Henry Garrido, executive director of the city’s largest public union, District Council 37, said in an interview. “Because at this point, there’s a new reality.”

Jeffery C. Mays contributed reporting.

The French government announced on Thursday that it had granted citizenship to more than 12,000 foreign essential workers to thank them for their service during the pandemic.

“These frontline workers have served the nation,” Marlène Schiappa, the French minister in charge of citizenship matters, said in a statement. “It is only natural that the nation should embrace them.”

Data from the Health Observatory of the Île-de-France region, an area that includes Paris, show that immigrants made up a quarter of essential workers who remained active during lockdowns. Of those working in the hospitals in the region, 23 percent are immigrants, though some may already be citizens.

In September 2020, France’s interior ministry reduced its legal residency requirement for citizenship applications from five years to two, and accelerated the application process for essential workers, including health care professionals, cashiers, child care providers and garbage collectors.

More than 16,000 such workers have applied for citizenship, and more than 12,000 have already received it, according to the interior ministry.