Covid-19: C.D.C. Reverses Testing Advice for Fully Vaccinated

Credit…Octavio Jones for The New York Times

In addition to revising its mask guidance on Tuesday, the Centers for Disease Control and Prevention also quietly updated its testing recommendations for people who are fully vaccinated against the coronavirus.

The agency now advises that vaccinated people be tested for the virus if they come into contact with someone with Covid-19, even if they have no symptoms. Previously, the health agency had said that fully vaccinated people did not need to be tested after exposure to the virus unless they were experiencing symptoms.

“Our updated guidance recommends vaccinated people get tested upon exposure regardless of symptoms,” Dr. Rochelle P. Walensky, the agency’s director, said in an email to The New York Times. “Testing is widely available.”

Fully vaccinated people should wear a mask in public indoor spaces after exposure, the agency said. Three to five days later, they should be tested for the virus.

If the results come back negative, they can stop wearing masks indoors. If results are positive, the infected should isolate at home for 10 days.

Although people who are fully vaccinated may still get infected with the virus, these breakthrough infections tend to be mild or asymptomatic. The vaccines authorized in the United States provide strong protection against the worst outcomes, including severe disease, hospitalization and death, including from the Delta variant.

The new testing recommendation came on the same day that the agency recommended that fully vaccinated people return to wearing masks indoors under some circumstances. When levels of community transmission are high, everyone, regardless of vaccination status, should wear masks indoors when they are in public, the agency now says.

The agency also recommended that vaccinated people in close contact with unvaccinated people, including children under age 12, consider wearing masks in public indoor spaces whatever the transmission rates in the local community. In a shift, the agency also recommended universal masking in schools.

For months, the C.D.C. had resisted recommending masks for vaccinated people, even as the highly contagious Delta variant spread and the World Health Organization recommended continued mask wearing.

The change was prompted by new data suggesting that even vaccinated people who are infected by Delta may carry large amounts of the virus and transmit it to others, Dr. Walensky said at a news briefing on Tuesday.

Apoorva Mandavilli contributed reporting.

Covid-19 vaccinations being offered Tuesday at the Rose E. McCoy Auditorium on the Jackson State University campus in Jackson, Miss. The state is seeing a steep rise in cases and deaths.
Credit…Rogelio V. Solis/Associated Press

Mississippi’s top state health officials warned on Wednesday of an “astounding” rise in Covid-19 cases that threatens to overwhelm some hospitals’ intensive care units. They ordered hospitals to forgo some elective surgeries and to adhere to a plan to transfer patients to other facilities with available beds when necessary.

The number of Covid-19 infections in the past two weeks was well over double the number recorded for the first half of July, the officials said at a news conference. Deaths rose by 51 percent over the same period and now average between three and four a day, according to the statistics presented.

Statewide, the statistics showed, more than 300 Covid-19 patients were in intensive care or on a ventilator, compared with a few dozen at the start of the month. Where intensive care units are full, some patients are being treated in emergency rooms, the officials said.

Rampant misinformation about the safety and effectiveness of vaccines is undercutting the state’s efforts, said Dr. Thomas Dobbs, the state health officer.

“We’re going to make the vaccine available, but you know, there’s a mountain of opposition to us from some folks,” he said. “We have gotten ourselves into this mess together, and we need to get ourselves out together.”

While the national outlook is also worsening quickly, Mississippi is one of a handful of states where the rate of infections is skyrocketing. Fewer than one half of adults have received at least one shot, putting the state at the bottom of the nation’s vaccination rate ranks and rendering much of its population vulnerable to the highly contagious Delta variant.

Dr. Dobbs said the flood of Covid-19 patients means hospitals in the state must forgo elective surgeries that require overnight stays and must be prepared to fly Covid-19 patients to other facilities if beds run short. He said that many health professionals are “absolutely worn out” from previous surges and that some hospital nurses are quitting — a trend that could make it harder to handle the ongoing spike.

Dr. Paul Byers, the state epidemiologist, called the rise in the number of daily infections “astounding.” He cited 72 long-term-care facilities where unvaccinated staffers have been largely spreading the virus, but he also mentioned settings like summer schools and cheerleading camps.

He said he expects cases to continue to escalate in the coming weeks. Asked to identify where in the state outbreaks are most severe, he said: “We are covered up with outbreaks.”

The bad news for baseball fans, posted outside the ballpark in Philadelphia on Wednesday. The Phillies-Nationals game was postponed by a coronavirus outbreak.
Credit…Laurence Kesterson/Associated Press

The Washington Nationals postponed their Wednesday night game against the Philadelphia Phillies after a dozen players and staff members tested positive for the coronavirus.

In a statement, the Nationals said the game was postponed to “allow for continued testing and contact tracing involving members of the Nationals organization.”

The wave of infections came after a Nationals shortstop, Trea Turner, left during the first inning of Tuesday night’s game against the Phillies after testing positive for the virus.

Dave Martinez, manager of the Nationals, told reporters that four players, including Turner, and eight staff members were among the positive cases, ESPN reported.

Mr. Martinez also told reporters he believed that one of the dozen cases was a person who is unvaccinated, according to ESPN.

The Nationals are among many M.L.B. teams that have been able to loosen safety protocols after reaching the 85 percent vaccination threshold set by the league. Players and coaches on these teams do not have to wear masks in the dugout or bullpen during games, can work out without masks in weight rooms and are subject to less frequent testing for the virus.

The Nationals had an outbreak at the beginning of the season that forced a series against the New York Mets to be postponed in April after four Nationals players and a staff member tested positive.

This month, after several New York Yankees players tested positive, that team had to postpone its July 15 game against the Boston Red Sox.

The Nationals and Phillies are set to make up the Wednesday game as part of a doubleheader on Thursday.

Administering a shot of the Johnson & Johnson vaccine in Milan on Wednesday. The single-dose formula can be stored in normal refrigeration.
Credit…Antonio Calanni/Associated Press

The Food and Drug Administration on Wednesday agreed to allow Johnson & Johnson to extend the shelf life of its coronavirus vaccine to six months.

The F.D.A.’s decision came as state health officials in the United States were growing increasingly concerned that doses of the vaccine would expire and go to waste. The vaccines were previously set to expire after four and a half months.

In a letter, the F.D.A. said its decision was “applicable to batches that might have expired prior to the issuance of this concurrence letter” and had been stored at the proper temperature, 2-8 degrees Celsius, or 35.6-46.4 Fahrenheit.

The single-dose Johnson & Johnson vaccine can be stored in normal refrigeration, which has helped states reach more isolated communities where it may be difficult to manage a two-dose vaccine like those made by Pfizer-BioNTech and Moderna. Both of those must be stored at much lower temperatures.

As of Wednesday, more than 13 million Americans had received the one-shot Johnson & Johnson vaccine, according to data from the Centers for Disease Control and Prevention.

The Pfizer-BioNTech vaccine has been the most widely administered in the United States, with more than 87 million Americans fully vaccinated with it. More than 63 million people in the United States have been fully vaccinated with the Moderna formula.

President Biden on Tuesday.
Credit…T.J. Kirkpatrick for The New York Times

President Biden will formally announce on Thursday that all civilian federal employees must be vaccinated against the coronavirus or be forced to submit to regular testing, social distancing, masking requirements and restrictions on most travel, two people familiar with the president’s plans said Wednesday.

White House officials said the administration is still reviewing the specific details of the policy, which the president is expected to announce in a speech from the White House. In a statement on Tuesday, Mr. Biden said his remarks will reveal “the next steps in our effort to get more Americans vaccinated.”

The president’s move is expected to be similar to an announcement on Wednesday by Gov. Andrew M. Cuomo of New York, who said that tens of thousands of state employees would be required to show proof of vaccination or submit to weekly testing. Mr. Cuomo also said that “patient-facing” health care workers at state-run hospitals would be required to be vaccinated as a condition of their employment. Two days earlier, New York City announced that all 300,000 municipal employees must be vaccinated or submit to weekly testing.

The federal plan will not force employees to get a shot unless they work directly with patients at hospitals run by the Veterans Affairs department. But public health officials are hoping that the prospect of extra burdens for the unvaccinated will help convince more people to get one.

Mr. Biden’s decision to embrace stricter vaccine rules for federal workers follow days of deliberations and reflect growing concern among top federal health officials about the spread of the highly contagious Delta variant, which poses a special threat to children, older Americans and those with weakened immune systems, including cancer patients. But that concern, officials said, must be balanced against the threat of a backlash that could drive opposition to vaccination. Recent research has shown that vaccines remain effective against the worst outcomes of Covid-19, including those involving the Delta variant.

Asked by a reporter on Tuesday whether he would require vaccinations for the nation’s nearly two million federal workers, Mr. Biden was blunt.

“That’s under consideration right now,” he said, adding, “But if you’re not vaccinated, you’re not nearly as smart as I thought you were.”

Mr. Biden did not provide details, but administration officials said the idea being debated was similar to the New York City mandate.

It was not clear if Mr. Biden was planning something similar for the military, although he does have the authority to do so. Defense Secretary Lloyd J. Austin III has said he would not be comfortable with a mandate until the Food and Drug Administration had fully approved the vaccine.

The officials said that this was not a matter of simply firing federal employees who refused to be vaccinated, but that the government could add burdens or restrictions — like extensive testing or a ban on all but essential travel — for those who did not willingly get the protections. They said there was evidence that making life inconvenient for those who refuse the vaccine works reasonably well to increase inoculation rates.

The move underscores the need by Mr. Biden and his top health advisers to grapple with the limits of his legal authority when it comes to forcing Americans to be vaccinated. Aides say the president has no power to order all Americans to get a shot, nor can he require children to be vaccinated as a condition of attending school; that is a function reserved for state or local governments.

A student received a second dose of the Pfizer vaccine at the Family Life Academy Charter School Middle School in the Bronx on Tuesday.
Credit…James Estrin/The New York Times

Pfizer reported on Wednesday that the power of its two-dose Covid vaccine wanes slightly over time, but nonetheless offers lasting and robust protection against serious disease. The company suggested that a third shot could improve immunity, but whether boosters will be widely needed is far from settled, the subject of heated debate among scientists.

So far, federal health officials have said boosters for the general population are unnecessary. And experts questioned whether vaccinated people should get more doses when so many people have yet to be immunized at all.

“There’s not enough evidence right now to support that that is somehow the best use of resources,” said Natalie Dean, a biostatistician at Emory University in Atlanta.

Still, the findings raise questions about how much the Pfizer vaccine will prevent infection in the months to come. And with coronavirus cases surging again in many states, the data may influence the Biden administration’s deliberations about delivering boosters for older people.

If third shots are cleared for the general population, the boosters would likely represent a multi-billion-dollar business for Pfizer.

In a study posted online but not yet peer-reviewed or published in a scientific journal, Pfizer and BioNTech scientists reported that the vaccine had a sky-high efficacy rate of about 96 percent against symptomatic Covid-19 for the first two months following the second dose. But the figure declined by about 6 percent every two months after that, falling to 83.7 percent after about four to six months.

Against severe disease, however, the vaccine’s efficacy held steady at about 97 percent.

“It’s not a big drop, but it is noteworthy,” Dr. Dean said. “Overall, they find that the vaccine is still performing very well, at very high efficacy.”

The study period ended before the rise of the Delta variant, the highly contagious version of the virus that now dominates in the United States and makes vaccines somewhat less effective against infection.

The findings come from 42,000 volunteers in six countries who participated in a clinical trial that Pfizer and BioNTech began last July. Half of the volunteers got the vaccine, while the other half received a placebo. Both groups received two shots spaced three weeks apart.

The researchers compared the number of people in each group who developed symptoms of Covid-19, which was then confirmed by a P.C.R. virus test. When the companies announced their first batch of results, the vaccine showed an efficacy against symptomatic Covid-19 of 95 percent.

In other words, the risk of getting sick was reduced by 95 percent in the group that got the vaccine, compared with the group that got the placebo. That result — the first for any Covid-19 vaccine — brought an exhilarating dose of hope to the world in December when it was riding what had been the biggest wave of the pandemic.

Since then, the Pfizer-BioNTech vaccine has made up the majority of shots that Americans have received, with more than 191 million doses given so far, according to the Centers for Disease Control.

In the new study, the researchers followed the volunteers for six months after vaccination, up to March 13. Over the entire period, the researchers estimated, the vaccine’s efficacy was 91.5 percent against symptomatic Covid-19. (The study did not measure the rate of asymptomatic virus infections.)

But within that period, efficacy did gradually drop. Between one week and two months after the second dose, the figure was 96.2 percent. In the period from two to four months following vaccination, efficacy fell to 90.1 percent. From four months after vaccination to the March cutoff, the figure was 83.7 percent.

Those figures still describe a remarkably effective vaccine, however, and may not convince critics that booster shots are widely needed.

Earlier on Wednesday, Pfizer reported that a third dose of its vaccine significantly increases blood levels of antibodies against several versions of the virus, including the Delta variant.

Results were similar for antibodies produced against the original virus and the Beta variant, which was first identified in South Africa. Pfizer and BioNTech expect to publish more definitive research in the coming weeks.

The announcement was a preliminary snapshot of data contained in an earnings statement. The finding has not been peer-reviewed nor published in a scientific journal. And although antibody levels are an important measure of immunity, they are not the only metric. The body has other defenses that turn back infection.

Pfizer also said in its statement that vaccines for children ages 5 through 11 years could be available as early as the end of September. The vaccine is already authorized in the United States for everyone ages 12 and up.

Pfizer’s vaccine brought in $7.8 billion in revenue in the last three months, the company said, and is on track to generate more than $33.5 billion this year.

The vaccine is poised to generate more sales in a single year than any previous medical product, and by a wide margin. The sales figures are poised to translate into billions of dollars in profit for the drugmaker.

Patrons in Grand Central Market in Los Angeles wore masks on Tuesday. California’s Department of Public Health recommended on Wednesday that people wear masks indoors regardless of vaccination status.
Credit…Alex Welsh for The New York Times

The new guidance about mask-wearing that the Centers for Disease Control and Prevention issued on Tuesday is not legally binding, leaving it up to state and local officials to decide whether and how to implement it. And that in turn depends greatly on local politics.

The C.D.C.’s recommendation that all adults in areas where the coronavirus is spreading rapidly go back to wearing masks indoors, even if they are fully vaccinated, was met with a sharp backlash in some areas, especially from political leaders in Republican-leaning states where mask mandates have been banned.

Officials in some states took the new guidance and swiftly ran with it. Others decided to take a wait-and-see approach.

In New Jersey, where eight of 21 counties meet the C.D.C.’s threshold, Gov. Philip D. Murphy, a Democrat, “strongly recommended” that all residents wear masks in indoor settings where the risk of spread may be high. In California, the public health department recommended residents wear masks in indoor public spaces, regardless of vaccination status. The moves came a day after the officials in Illinois joined the C.D.C. in recommending face coverings, and after Nevada issued a mask mandate.

Dr. Ngozi Ezike, director of the Illinois Department of Public Health, said that even though current vaccines are effective, including the highly contagious Delta variant, “we are still seeing the virus rapidly spread among the unvaccinated,” increasing the risk for everyone.

Gov. Steve Sisolak, a Democrat of Nevada, went further, reinstating a mask mandate set to take effect on Friday for all residents in indoor public spaces in counties with high rates of transmission, including Clark County, home to Las Vegas.

In Washington State, Gov. Jay Inslee urged all residents on Wednesday to follow the C.D.C.’s new mask guidance, but did not issue a mandate.

Other jurisdictions, including Delaware, the District of Columbia, and New York, were among the jurisdictions saying that said they would review the C.D.C.’s guidance before making any decisions. While all of New York City currently exceeds the coronavirus transmission threshold that the C.D.C. set to determine where indoor masking is needed, Mayor Bill de Blasio said at a news conference on Wednesday that the city was still evaluating the guidance and the research and data that underpinned it.

And several Republican governors just said no, including Greg Abbott of Texas, Doug Ducey of Arizona, Pete Ricketts of Nebraska, Kim Reynolds of Iowa, and Brian Kemp of Georgia. Conservatives in those states have often cast public health measures as an attack on freedom.

“I’m concerned that this guidance will be used as a vehicle to mandate masks in states and schools across the country, something I do not support,” Ms. Reynolds said in a statement.

Mr. Abbott, who signed an executive order in May preventing local governments from requiring masks, said that wearing a face covering was a matter of personal responsibility.

“Every Texan has the right to choose whether they will wear a mask or have their children wear masks,” Mr. Abbott wrote in a tweet.

Meanwhile, Apple said it will start requiring employees and customers to wear masks regardless of their vaccination status in certain stores across the country in accordance with the new C.D.C. guidelines.

C.D.C. officials also called on Tuesday for universal masking for teachers, staff, students and visitors in schools, regardless of vaccination status and transmission rates of the virus. Some school districts in Alabama and Georgia did not wait for state governments to weigh in, and immediately instituted their own mask requirements. Mr. Inslee of Washington said his state would retain its school mask mandate for students and staff.

In Florida, where new case reports have surged nearly tenfold over the last month to an average of more than 10,000 a day, Gov. Ron DeSantis of Florida, a Republican, issued a statement encouraging parents in his state to decide what’s best for their children when it comes to masking.

The governor did not address the new guidance about vaccinated adults at a news conference in Milton, Fla., on Wednesday. Florida never had a statewide mask mandate.

Mayor Daniella Levine Cava of Miami-Dade County, Fla., said at a news conference on Wednesday that masks would be required for employees and visitors at all indoor county facilities.

“I have pledged from the beginning that if we see a spike in the positivity rates that we would take all the necessary steps to protect the community, including making updated recommendations,” she said.

Other jurisdictions, like Los Angeles County and St. Louis County, Mo., had reinstated mask mandates even before the C.D.C.’s announcement.

But in a sign of the political challenges some local officials face, the St. Louis County Council voted on Tuesday evening to repeal the order. The move came a day after Attorney General Eric Schmitt of Missouri, a Republican, filed a lawsuit seeking to halt implementation of the county mandate, which is still in effect in the city of St. Louis.

On Wednesday, Mr. Schmitt wrote on Twitter that he plans to sue Kansas City, Mo., as well, following an announcement by Mayor Quinton Lucas that he would reimpose a mask mandate.

In Georgia, Mayor Keisha Lance Bottoms of Atlanta on Wednesday issued a mask mandate in indoor public spaces, even after Gov. Kemp said he opposed them.

“Georgia is not moving backwards,” he said on Twitter.

The Biden administration asked White House staffers on Tuesday to wear masks indoors, and the Office of Management and Budget detailed new mask rules for federal agencies. In an email obtained by The New York Times, the agency said, “In areas of substantial or high community transmission, agencies must require all federal employees, on-site contractors, and visitors, regardless of vaccination status, to wear a mask inside of federal buildings.”

Alan Rappeport and Michael Gold contributed reporting.

Orange County, Fla., home to Disney World, has issued a state of emergency due to rising cases. 
Credit…John Raoux/Associated Press

Starting Friday, Disney World in Florida and Disneyland in California will require all guests older than 2 to wear masks in indoor spaces, reversing its policy that allowed fully vaccinated guests to go without them.

The change was announced after the Centers for Disease Control and Prevention recommended on Tuesday that Americans, regardless of vaccination status, wear face masks in indoor public spaces in areas of the country with high rates of virus transmission.

Mayor Jerry L. Demings of Orange County, Fla., where Disney World is located, signed an executive order on Wednesday declaring a state of local emergency as cases rose in the county and said that all nonunion county employees must be fully vaccinated by the end of September.

“I urge residents and visitors — vaccinated and unvaccinated — to wear a mask while indoors and to follow updated C.D.C. guidelines,” Mr. Demings wrote on Twitter. Florida bars its counties from enforcing mask mandates.

Over the past two weeks, coronavirus infections in the county have increased by 184 percent, and hospitalizations have risen by 116 percent, according to a New York Times database.

Disney World’s new policy could draw some backlash from Gov. Ron DeSantis of Florida, a Republican, who has opposed any new restrictions and who defiantly criticized the new C.D.C. guidance about mask-wearing indoors and in schools.

“I think it’s very important we say, unequivocally, ‘No to lockdowns, no to school closures, no to restrictions, no mandates,’” Mr. DeSantis said in Salt Lake City at a gathering of the American Legislative Exchange Council, a conservative lobbying group.

In Florida, which has never imposed a statewide mask mandate and has recently seen a sharp rise in virus cases and hospitalizations, the public university system issued a letter on Wednesday strongly urging students to be vaccinated before classes start in the fall. And the new mask guidance from the C.D.C. prompted Miami-Dade County to reinstitute an indoor mask mandate at county facilities.

Mr. DeSantis has said that he thinks mask requirements are counterproductive.

“I get a little bit frustrated when I see some of these jurisdictions saying, ‘Even if you’re healthy and vaccinated, you must wear a mask because we’re seeing increased cases,’” he said on July 21. “Understand what that message is sending to people who aren’t vaccinated: It’s telling them that the vaccines don’t work. I think that’s the worst message that you can send to people at this time.”

Resuming indoor mask rules is less politically fraught in California, where Gov. Gavin Newsom, a Democrat, has said he planned to work closely with the C.D.C. Mr. Newsom announced earlier this week that the state would require two million health care workers and 246,000 state employees to get vaccinated or undergo frequent testing starting next month.

Disney was not the only company that reversed course in response to the C.D.C.’s advice. Apple said it would start requiring employees and customers, regardless of their vaccination status, to wear masks in certain stores across the country.

Gov. Andrew Cuomo of New York announced a vaccine or testing mandate for all public employees on Wednesday.
Credit…Mary Altaffer/Associated Press

Responding to lagging vaccination rates and a rise in coronavirus cases, Gov. Andrew M. Cuomo said on Wednesday that New York’s tens of thousands of state employees would be required to show proof of vaccination or face weekly testing.

The governor also announced a much stricter mandate for state-run hospitals, saying that all “patient-facing” health care workers at those facilities would be required to be vaccinated, without the option of regular testing instead.

Mr. Cuomo’s announcement comes two days after Mayor Bill de Blasio announced a similar requirement for New York City’s government work force of 300,000 employees.

Much of the nation is grappling with the rapid spread of the Delta coronavirus variant. Earlier this week, Gov. Gavin Newsom of California announced his own requirement that would cover 246,000 state government employees, as well as two million health care workers in the public and private sectors.

The North Carolina Department of Health and Human Services will require all workers and volunteers at state-operated facilities to be fully vaccinated or receive an approved medical or religious exemption by Sept. 30, according to a statement sent to The New York Times on Wednesday. Officials did not respond to questions about whether those with exemptions will be required to undergo testing.

President Biden plans to formally announce on Thursday that all civilian federal employees must be vaccinated against the coronavirus or be forced to submit to regular testing, social distancing, mask requirements and restrictions on most travel, two people familiar with the president’s plans said Wednesday. Such a policy would be a stark shift for a president who has grappled with the authority he has to force Americans to get vaccinated. Mr. Biden is expected to say more about his plans later this week.

The increasing support among government officials for vaccine mandates, which have met with pushback from some unions, underscores their concern with a far more contagious variant that poses a special threat to children, and older and unvaccinated people.

“We’re working with our unions to implement this quickly and fairly,” Mr. Cuomo, a third-term Democrat, said during remarks to a state business group on Wednesday.

The new state policy will go into effect by Labor Day, he said.

Earlier this week, Mr. Cuomo had shied away from imposing such a requirement on the state’s work force, arguing that most “public-facing” employees were municipal workers, and suggesting it was more of a decision for localities.

But Mr. Cuomo’s shift in stance appeared inevitable following Mr. de Blasio’s announcement and news that a similar move was under consideration at the federal level.

Mr. Cuomo highlighted the urgency behind the change, noting the steady rise in coronavirus cases statewide: About 2,200 new cases were reported on Tuesday, up from 275 on a month ago, on June 28.

Currently, most New York State employees are not subject to regular testing, except for those working in some congregate settings like colleges and universities.

For example, staff and faculty members at the State University of New York and the City University of New York are required to get tested for the coronavirus weekly unless they are fully vaccinated, a policy similar to the one Mr. de Blasio announced this week.

The public universities will require proof of vaccination from students attending in-person classes once the Food and Drug Administration fully approves the vaccines, although that could be months away. The vaccines are now being administered under an emergency use authorization.

Dan Levin contributed reporting.

Most people wore masks at Grand Central Terminal in Manhattan on Tuesday.
Credit…Brittainy Newman for The New York Times

All of New York City currently exceeds the threshold for coronavirus transmission outlined by the Centers for Disease Control and Prevention on Tuesday in its guidance recommending that vaccinated people resume wearing masks in public indoor spaces in areas where the virus is raging.

Agency officials said that Americans should wear masks indoors in parts of the country that have recorded more than 50 new infections per 100,000 residents over the previous week, or where more than 8 percent of tests are positive for infection over that period.

All five counties in New York City fall under those parameters. Staten Island, which has again become a virus hot spot and has some of the lowest vaccination rates in the city, recorded 109 cases per 100,000 residents last week, according to the C.D.C. In Brooklyn and Manhattan, 78.1 and 70.4 cases were recorded, respectively, while the Bronx (58.6) and Queens (56.4) are both closer to the 50-case benchmark set by the C.D.C.

The agency’s recommendations are not binding, and on Wednesday, it remained unclear whether New York City would alter its mask requirements to reflect the new guidelines.

Mayor Bill de Blasio said at a news conference that the city was still evaluating the guidance and the research and data that underpinned it.

“We got it less than 24 hours ago, and it is complicated information,” Mr. de Blasio said. “So our health team is reviewing and we’ll have more to say on it in the next few days.”

As they weighed the C.D.C.’s suggestions, city health officials continued to urge residents to get vaccinated. Starting Friday, the city will give $100 to residents who get their first dose of a vaccine at city-run vaccination sites.

Mr. de Blasio has in recent days emphasized the need for vaccine mandates as the pace of inoculations has slowed in the city. But on Wednesday, he said that the city still believed incentives could work hand-in-hand with more forceful vaccine guidance.

“There are a huge number of New Yorkers open to vaccination but just haven’t quite gotten there,” he said. “I think when someone says here’s $100 for you, that’s going to make a big impact.”

Officials at the C.D.C. also called for universal masking in schools, a policy that New York City’s public school system, the nation’s largest, had already said it would keep in place.

Currently, vaccinated individuals are largely not required to wear masks in New York State, though they are required on the city’s buses, subways and trains.

Google’s campus in Mountain View, Calif. The company will delay its return to office and mandate vaccines for its workers.
Credit…Christie Hemm Klok for The New York Times

Google said Wednesday that it would require employees who returned to the company’s offices to be vaccinated against the coronavirus. It also said it would push back its official return-to-office date to mid-October from September, joining a host of other companies whose plans have been scrambled in recent days by the spread of the highly contagious Delta variant.

Sundar Pichai, the chief executive of Alphabet, Google’s parent company, announced the news in a note to employees, which was reviewed by The New York Times.

“Getting vaccinated is one of the most important ways to keep ourselves and our communities healthy in the months ahead,” Mr. Pichai wrote. He added that the vaccine mandate would apply to U.S. office locations “in the coming weeks” and to other regions “in the coming months.”

Google has more than 144,000 employees globally. A Google spokeswoman said the company did not have any current vaccination rates to share, though Mr. Pichai wrote that it was “encouraging to see very high vaccination rates” among employees in places where vaccines were widely available.

Mr. Pichai also said in the note that Google’s voluntary work-from-home policy was being extended through Oct. 18. Previously, employees had been planning to return in September, though no specific date had been set.

“We recognize that many Googlers are seeing spikes in their communities caused by the Delta variant and are concerned about returning to the office,” Mr. Pichai wrote. “This extension will allow us time to ramp back into work while providing flexibility for those who need it.”

The decision followed a similar announcement from Apple, which said last week that it would push back to October, from September, the date by which employees would need to return to its offices.

The companies are among many in tech that are changing their office plans as coronavirus cases spike. Lyft said on Wednesday that it would not require employees to return to the office until February, while Twitter said it would close its newly reopened offices in San Francisco and New York and indefinitely postpone other reopening plans.

Some Google employees have been returning to work in the office on a voluntary basis. In California, as the Delta variant of the coronavirus has surged, workers began donning masks in Google offices again.

Silicon Valley tech companies like Google led the push to remote work in the beginning of the pandemic, but Google has not fully pivoted away from office work, and it has said it expects most employees to eventually return to in-person work at least three days a week.

The company said in March that it would spend $1 billion on California developments this year, including two office complexes in Mountain View. It is also building a 7.3 million-square-foot office space in San Jose.

A child receiving a yellow fever vaccine in Sao Paulo, Brazil, in 2018. Routine childhood vaccinations have dropped off in Latin America  since the pandemic began.
Credit…Andre Penner/Associated Press

The coronavirus pandemic is opening the way for other preventable diseases to surge across Latin America and the Caribbean, interfering with routine inoculations and medical treatment in one of the world’s hardest-hit regions, World Health Organization officials warned on Wednesday.

There has been a sharp decline in measles vaccinations throughout the region, and a recent survey found that the pandemic had slowed efforts to diagnose and treat viral hepatitis B and C infections throughout Latin America and the Caribbean.

“More than 300,000 children, mostly in Brazil and Mexico, missed out on their routine immunizations last year, leaving them vulnerable to deadly yet preventable infections,” said Dr. Carissa F. Etienne, the director of the Pan American Health Organization, a part of the W.H.O.

“If we do not reverse these trends, we risk an avalanche of worsening health issues in the Americas,” she added. “Soon, Covid-19 will not be the only health crisis demanding countries’ attention.”

Though overall caseloads have declined in the region since the spring, Covid-19 continues to take a devastating toll, and several Latin American nations, including Argentina, Colombia, Cuba, Ecuador and Paraguay are “among the countries reporting the world’s highest weekly death rates,” Dr. Etienne said at a weekly briefing. She warned that “too many places have relaxed the public health and safety measures that have proven so effective against this virus.”

Officials voiced particular concern about Cuba, which is reporting its highest rates of new cases and deaths since the pandemic began. Hot spots have also been detected in parts of Argentina, Colombia and Mexico, and new cases have risen sharply in the United States.

Though vaccines have been plentiful in the United States, Canada, Chile, Uruguay and a few other countries in the Americas, they have been scarce elsewhere. Only one-sixth of the population of Latin America and the Caribbean has been fully vaccinated.

One of the most extreme examples is Haiti, which was only recently able to begin its vaccination campaign after a donation of shots from the United States.

Maureen McKinney’s husband was one of fifteen residents who died from a coronavirus outbreak at the Prestige Post-Acute and Rehab Center in Ellensburg, Wash.
Credit…Chona Kasinger for The New York Times

As the Delta variant raises fresh concerns about the safety of the nation’s nursing homes, the Biden administration has quietly reversed a Trump administration policy that limited the fines levied on facilities that endangered or injured residents.

Deaths in nursing homes account for nearly one-third of the U.S. pandemic’s overall death toll. They peaked at the end of last year, but have plummeted since the introduction of the Covid-19 vaccines.

Even so, advocates and some officials say, inadequate staffing, shortages of protective equipment and poor infection control remain concerns at the nation’s 14,000 skilled nursing facilities.

While 81 percent of nursing home residents are now fully vaccinated, only 58 percent of workers in the homes are immunized, according to federal data, heightening the risk of outbreaks even among vaccinated residents.

There are signs of a creeping rise in infections in nursing homes, particularly among workers. The Centers for Disease Control and Prevention is investigating the source of outbreaks in Colorado nursing homes where vaccination rates may be low.

The policy favoring lower penalties, adopted in 2017 by the Trump administration, directed regulators at the Centers for Medicare and Medicaid Services to shift away from fining a nursing home for each day it is out of compliance with federal standards. The relaxed policy reduced many penalties to a single fine, effectively lowering the penalties to a maximum of $22,000, instead of amounts running into hundreds of thousands of dollars.

Many of the nursing homes that are cited for poor infection controls, failing to protect residents from avoidable accidents, neglect, mistreatment and bedsores, are repeat offenders. Larger fines act as a deterrent and are more likely to signal strong enforcement of the rules, according to Toby Edelman, a senior policy attorney at the Center for Medicare Advocacy.

Travelers at Heathrow airport in London last month.
Credit…Andy Rain/EPA, via Shutterstock

Fully vaccinated travelers from the United States and most of the European Union will be allowed to enter England and Scotland without quarantining upon arrival starting Aug. 2, the British authorities said on Wednesday, as they sought to attract tourists after months of restrictions.

Prime Minister Boris Johnson said Wednesday that he wanted Americans to travel to England “freely.” The Scottish government quickly followed London’s lead. Last week, the British government relaxed all but a handful of restrictions in England despite a major surge in infections. Cases have since declined, surprising experts and government officials who had expected them to keep rising.

On Twitter, Grant Shapps, the transport secretary, wrote, “We’re helping reunite people living in the U.S. and European countries with their family and friends in U.K.”

As of Aug. 2, the rules will apply equally to travelers from the United States and most of the European Union, as well as Iceland, Norway and Switzerland if they have been vaccinated with shots authorized by either American or European drug regulators, Mr. Shapps said. The exception is travelers from France, who will still have to self-isolate for 10 days. He said travelers will need a negative coronavirus test before a trip and another upon arrival.

The government has been criticized for discriminating between travelers who were vaccinated in Britain and those inoculated elsewhere, without any medical justification. Vaccinated people arriving in England from most “amber list” countries, those with moderately high transmission, have been required to self-isolate — unless they received their shots in Britain.

Most European countries have opened to American tourists after the European Union recommended lifting a ban on nonessential travel last month. Yet E.U. and British residents are still mostly banned from traveling to the United States unless they are U.S. citizens.

The Biden administration said on Monday that it would continue to restrict the entry of Europeans and others into the United States, citing concerns that infected travelers may contribute to a further spread of the very contagious Delta variant. The State Department is advising American travelers not to go to Britain, Spain or Portugal, and to reconsider travel to other parts of Western Europe.

Few experts are willing to draw definitive conclusions from the overall decline in cases in Britain over the past week, which could reflect transient factors like the school summer break, the end of the European soccer championships or fewer tests being administered.

But if the trend is sustained, it raises a tantalizing prospect that Mr. Johnson may have bet correctly that the country could withstand a return to normalcy, even with the Delta variant circulating widely.

Mark Landler contributed reporting.

Kevin McCarthy, the House Minority leader, at the U.S. Capitol in May, before the mask mandate was lifted. The House of Representatives is requiring masks again, following new C.D.C. guidance issued this week.
Credit…Stefani Reynolds for The New York Times

The House of Representatives will once again require all lawmakers and staff members to wear masks inside, a sharp reversal of policy as growing fears about the Delta variant reach the doorstep of Congress. Senators will be encouraged to mask up, too, but are not required to do so.

In a memo late Tuesday night, Dr. Brian P. Monahan, Congress’s top doctor, said he was recommending the change based on new C.D.C. guidance and the nature of the Capitol, where thousands of people traveling from across the country mix each week. Speaker Nancy Pelosi made the change official on the House floor Wednesday morning.

“For the Congress, representing a collection of individuals traveling weekly from various risk areas (both high and low rates of disease transmission), all individuals should wear a well-fitted, medical-grade filtration mask (for example an ear loop surgical mask or a KN95 mask) when they are in an interior space,” Dr. Monahan wrote to House officials.

In a letter to top Senate leaders, Dr. Monahan dispensed the same advice but stopped short of recommending a mask mandate. The Senate is a smaller body, and for much of the pandemic, its members wore masks voluntarily. Most Senators are vaccinated.

The House triumphantly dropped its longtime mask requirement six weeks ago in a show of optimism that the grip of the pandemic was loosening.

Since then, at least one House lawmaker and an aide to Speaker Nancy Pelosi have tested positive for the coronavirus after being fully vaccinated. Others on Capitol Hill have gone into voluntary quarantine after exposure to individuals who were sick with Covid-19, and on Wednesday, the Senate Homeland Security Committee called off a business meeting after staff members tested positive for the virus, a committee aide said. At the same time, new cases have skyrocketed across the country.

Like broader mask guidance from the C.D.C. and aggressive interventions being considered by President Biden to increase the nation’s vaccination rate, the new mask mandate in the House is likely to test the patience of a weary public and the opposition Republican Party, which is eager to accuse Democrats of undermining confidence in vaccines and jeopardizing the health of the recovering economy. Republicans in the House immediately protested and raised the prospect that they may refuse to comply.

“Make no mistake — The threat of bringing masks back is not a decision based on science, but a decision conjured up by liberal government officials who want to continue to live in a perpetual pandemic state,” Representative Kevin McCarthy, Republican of California and the minority leader, wrote on Twitter.

House rules say that any lawmaker who does not wear a mask in specified spaces in the Capitol complex can be fined $500 or more. Several Republicans were fined earlier this year for that reason. But it is unclear what Ms. Pelosi and other House leaders would do if many Republican members refuse to go along.

Signs of such resistance were seen on Wednesday morning minutes after Ms. Pelosi announced the updated rules. When a staff member designated to work on the House floor handed a mask to Representative Lauren Boebert, Republican of Colorado, she tossed it back at the person, according to another aide who witnessed the exchange and requested anonymity to describe it.

Asked about Mr. McCarthy’s comments on Wednesday, Ms. Pelosi did little to hide her scorn. “He’s such a moron,” Ms. Pelosi was heard to say by reporters.

Ms. Pelosi’s spokesman later said he could not verify her precise words, but that the speaker indeed felt that Mr. McCarthy’s position on the issue “is moronic.”

Senate Republicans have taken a more conciliatory tack, with their top leaders pleading with conservatives who have refused vaccination to get inoculated. For instance, Senator Mitch McConnell of Kentucky, the minority leader, plans to begin using tens of thousands of dollars in campaign funds to run radio ads in his home state promoting the coronavirus vaccines as a “modern medical miracle” and urging his constituents to accept them.

“If you haven’t been vaccinated, do the right thing for you — for your family — and get vaccinated right now,” said Mr. McConnell, who recounts his own fight with polio in the ad. “I’m Mitch McConnell and I approved this message.”

Administering vaccines in Hammanskraal, South Africa, this month. The U.S. is sending 5.6 million shots to the country as part of a pledge to share 80 million doses globally.
Credit…Alet Pretorius/Associated Press

The United States is ramping up vaccine deliveries to Africa as a third wave of the pandemic continues to accelerate across the continent.

On Wednesday, Washington was scheduled to ship almost 10 million Covid-19 vaccines to two of Africa’s most populous nations, with 5.6 million Pfizer doses going to South Africa and four million Moderna doses to Nigeria. The deliveries are part of a pledge President Biden made in June to share 80 million doses globally — with about 25 million doses expected to arrive in 49 African states.

Over the past two weeks, Covax, the global vaccine partnership, has, in collaboration with the African Union, delivered millions of Johnson & Johnson doses from the United States to countries including Cameroon, the Central African Republic, Djibouti, Gambia, Lesotho, Niger, Tunisia, and Zambia. The latest shipments to Nigeria and South Africa brings the total number of vaccines donated to 16.4 million doses.

The donations from the United States come as Africa continues to lag behind the rest of the world in Covid vaccination. Only about 21 million of the continent’s 1.3 billion people have been fully vaccinated, according to the World Health Organization, with 77 percent of all the doses received already administered. At current rates, almost two-thirds of African countries will not reach a W.H.O. target of vaccinating 10 percent of their populations by the end of September.

Vaccine availability in Africa has been hampered because wealthy nations have bought excess doses, and was set back further with India’s decision in March to cut back on vaccine exports, particularly the supplies from the Serum Institute of India that Covax had been relying on. Because of those issues, the African continent will most likely not be able to meet the slightly longer-term goal of vaccinating 20 percent of the population by the end of 2022.

The continent is experiencing vaccine shortages even as the severe third wave overwhelms health care systems and pushes countries to institute lockdowns and extend overnight curfews. The current surge in cases has been attributed to a lack of inoculation; loose compliance with public health measures, such as mask wearing and social distancing; and the spread of more contagious variants. More than 20 African countries have seen cases rise by more than 20 percent for at least two weeks, according to the W.H.O., with the Delta variant reported in 26 countries.

The W.H.O. has said that political crises in several countries threaten to undermine efforts to vaccinate people and curb the virus. That includes Ethiopia, where the conflict in Tigray is set to intensify, and Eswatini, where deadly antigovernment protests broke out this month. In South Africa, the looting and killings that followed the imprisonment of former President Jacob Zuma have had a negative impact on vaccination efforts in the eastern province of KwaZulu-Natal, Dr. Matshidiso Moeti, the health organization’s Africa director, has said.

Both the W.H.O. and the Africa Centers for Disease Control and Prevention have said that vaccine deliveries will continue to ramp up. Besides the United States, millions of doses from the European Union are expected to arrive in the coming weeks. And Britain said it would start delivering nine million doses of the Oxford-AstraZeneca vaccine this week to countries including Kenya. China also raised its vaccine pledges to Africa this month, sending Sinovac doses to nations including Tanzania and Uganda. Covax has said that it will deliver over 500 million vaccines to Africa by the end of the year.

Vaccines are now reaching countries like Tanzania, which previously made no effort to secure doses and whose former president played down the pandemic and pronounced that God helped eliminate the virus.

On Saturday, Tanzania received over one million Johnson & Johnson doses from the United States. On Wednesday morning, President Samia Suluhu Hassan received her Covid-19 vaccine, beginning the country’s vaccination campaign.

During the ceremony, Ms. Hassan assured the public of the safety of the shots and urged those vaccinated to continue following public health measures.

“I have agreed to be vaccinated today,” Ms. Hassan said, “just as my body has been vaccinated a lot since childhood.”

Standing in line for Covid-19 vaccines in Bangalore, India, on Tuesday. The situation has improved lately in the country, which was the epicenter of the pandemic a few months ago. 
Credit…Jagadeesh Nv/EPA, via Shutterstock

On a global scale, the latest wave of the pandemic appears to be cresting at a lower level than those of the winter and spring, but the pattern differs markedly from place to place, as each nation endures its own particular drama.

The patchwork reflects the radically different paths the coronavirus takes from nation to nation, depending not only on vaccines, but on geographic isolation, the spread of the highly infectious Delta and other variants, social and economic restrictions, public compliance and an element of luck.

Conditions have improved substantially in places like India and South America that a few months ago were among the hardest-hit in the world, according to the Center for Systems Science and Engineering at Johns Hopkins University.

In May, India reached about 400,000 new infections and 4,000 Covid-19 deaths officially reported per day, though experts said the true toll was much higher. On Monday, the daily tally of new cases in India dipped below 30,000 for the first time in more than four months, and the country is now reporting fewer than 1,000 deaths a day.

The most troubled countries now are a scattered assortment, not concentrated in any one region. Botswana, Kazakhstan, Malaysia and Spain have among the highest infection rates in the world, with numbers still climbing. Indonesia, which was recording more cases than any other country this month, remains badly affected, but the pace there has eased somewhat.

In many countries, rates of new cases are relatively low but have risen sharply in recent days. They include countries with some of the highest inoculation rates, like Finland, France, Germany, Ireland, Israel and the United States, where restrictions have relaxed and the Delta variant has surged.

Vaccination rates range from more than 80 percent of adults in some countries to less than 1 percent in others, including in many of the world’s poorest nations, according to data from the Our World in Data project at the University of Oxford.

Britain has become an outlier: One of the most-vaccinated parts of the world, it has a high (though declining) infection rate.

Globally, more than 500,000 new cases are being recorded daily, compared with more than 800,000 three months ago. But comparisons like that are fraught, because official reporting practices vary widely from region to region. The picture is especially difficult to gauge across most of Africa, where both testing and vaccines remain scarce.