Coronavirus Live Updates: Scientists See Signs of Lasting Immunity, Even After Mild Infections

Even mild Covid-19 cases confer ‘durable immunity,’ new studies find.

Scientists who have been monitoring immune responses to the coronavirus for months are now starting to see encouraging signs of strong, lasting immunity, even in people who developed only mild symptoms of Covid-19, a flurry of new studies has found.

Disease-fighting antibodies, as well as immune cells called B cells and T cells capable of recognizing the virus, appear to persist months after infections have resolved — an encouraging echo of the body’s robust immune response to other viruses.

“This is exactly what you would hope for,” said Marion Pepper, an immunologist at the University of Washington and an author on one of the new studies, which is currently under review at the journal Nature. “All the pieces are there to have a totally protective immune response.”

“This is very promising,” said Smita Iyer, an immunologist at the University of California, Davis, who is studying immune responses to the coronavirus in rhesus macaques and was not involved in these papers. “This calls for some optimism about herd immunity, and potentially a vaccine.”

Research on the coronavirus is proceeding so quickly, and in such volume, that the traditional review process often cannot keep pace. For the studies discussed here — as with un-peer-reviewed studies in general — The Times arranged for several experts to read and evaluate them.

Although researchers cannot forecast how long these immune responses will last, many experts consider the data a welcome indication that the body has a good chance of fending off the coronavirus if exposed to it again.

“Things are really working as they’re supposed to,” said Deepta Bhattacharya, an immunologist at the University of Arizona and an author on one of the new studies, which has not yet been peer reviewed.

Protection against reinfection cannot be fully confirmed until there is proof that most people who encounter the virus a second time are actually able to keep it at bay, Dr. Pepper said. But the findings could help quell recent concerns over the virus’s ability to dupe the immune system into amnesia, leaving people vulnerable to repeat bouts of disease.

Fearing a ‘twindemic,’ health experts push urgently for flu shots.

As public health officials look to fall and winter, the specter of a new surge of Covid-19 gives them chills. But there is a scenario they dread even more: a severe flu season resulting in a “twindemic.”

Even a mild flu season could stagger hospitals already coping with Covid-19 cases. And although officials don’t know yet what degree of severity to anticipate this year, they worry that large numbers of people could forgo flu shots, increasing the risk of widespread outbreaks.

Flu, a life-threatening respiratory illness that crowds emergency rooms and intensive care units, shares symptoms with Covid-19: fever, headache, cough, sore throat, muscle aches and fatigue. Flu could leave patients vulnerable to a harsher attack of Covid-19, doctors believe, and that coming down with both viruses at once could be disastrous.

The concern about a twindemic is so great that officials around the world are pushing the flu shot even before it becomes available in clinics and doctors’ offices. Dr. Robert Redfield, director of the U.S. Centers for Disease Control and Prevention, has been talking it up, urging corporate leaders to figure out ways to inoculate employees. The C.D.C. usually purchases 500,000 doses for uninsured adults but this year ordered an additional 9.3 million doses.

Because common places of access, including offices and school health clinics, will be largely off limits, pharmacies and supermarkets are expected to play greater roles in administering the shots. As of this week, CVS and Walgreens will have doses ready.

The flu vaccine is rarely mandated in the U.S. except by some health care facilities and nursery schools, but this month the statewide University of California system announced that because of the pandemic, it is requiring all 230,000 employees and 280,000 students to get the flu vaccine by November 1.

Fighting flu proactively during the continuing pandemic presents significant challenges: not only how to administer the shot safely and readily, but also how to prompt people to get a shot that a majority of Americans have typically distrusted, dismissed and skipped.

Public campaigns will describe the shot as a critical weapon during the pandemic. “Hopefully people will say, ‘There’s no Covid vaccine so I can’t control that, but I do have access to the flu vaccine and I can get that,’” said Patsy Stinchfield, senior director of infection prevention at Children’s Minnesota and a member of the C.D.C.’s influenza work group. “It gives you a little power to protect yourself.”

GLOBAL ROUNDUP

A cluster of cases prompts New Zealand to delay its election.

New Zealand on Monday said it would postpone its national election by four weeks as a cluster of new virus cases continues to spread in Auckland, its largest city.

Prime Minister Jacinda Ardern, who has the sole authority to determine when people cast ballots, said she had consulted with all the major parties before deciding to move the election from Sept. 19. to Oct. 17. The latest possible date she could have chosen was Nov. 21.

Ms. Ardern called the new date a compromise that “provides sufficient time for parties to plan around the range of circumstances we could be campaigning under, for the electoral commission to prepare, and for voters to feel assured of a safe, accessible and critical election.”

But she ruled out further change. Even if the outbreak worsens, she said, “we will be sticking with the date we have.”

The election delay came as the mysterious cluster of new cases grew to 58 on Monday.

Health officials are still scrambling to test thousands of workers at airports and other points of entry, along with quarantine facilities and a frozen food warehouse, as they try to determine how the virus re-emerged last week after 102 days without known community transmission in the country.

Pressure on Ms. Ardern and her Labour Party to change the date had been building for several days.

With a Level 3 lockdown in Auckland putting a stop to campaigning, the leaders of other major parties argued that a free and fair election was impossible on the original date.

Winston Peters, the deputy prime minister and leader of the New Zealand First Party, Ms. Ardern’s coalition partner, said in a letter to Ms. Ardern last week that community transmission in Auckland was already disrupting the campaign. Until the city’s alert level drops, he said, the “playing field is hopelessly compromised.”

The National Party’s leader, Judith Collins, said she would prefer that the election be moved to next year, but that would require approval from 75 percent of Parliament. She said the election would be impossible “if a lot of people are frightened to leave your house or even frightened of having postal ballots.”

Ms. Ardern, however, said Monday that New Zealand needed to move forward.

“Covid is the world’s new normal,” she said. “Here in New Zealand, we are working as hard as we can to make sure our new normal disrupts our lives as little as possible.”

In other developments around the world:

• Australia recorded its deadliest day of the pandemic, reporting 25 deaths in the previous 24 hours on Monday, all in the state of Victoria. The country has had more than 23,000 cases and more than 400 deaths, according to a New York Times database.

• Also in Australia, state officials in New South Wales have apologized for their handling of an outbreak on the Ruby Princess cruise ship in March, when 2,650 passengers were allowed to disembark in Sydney without adequate testing. The ship was ultimately linked to at least 900 infections and 28 deaths, according to an independent report published on Friday.

• India reported 941 deaths on Monday, taking the country’s death toll past 50,000. Last week, India overtook Britain as the country with the world’s third-highest number of deaths, after the United States, Brazil and Mexico.

• Japan’s economy shrank by 7.8 percent in the second quarter of the year, posting its worst performance on record as the country reeled from the effects of the pandemic.

• South Korea reported 197 new cases on Monday, as health officials tested thousands of people for the coronavirus in an effort to contain an outbreak in the Seoul metropolitan area. Mass infections at two churches in Seoul and the surrounding province of Gyeonggi have helped push the country’s daily caseload into triple digits in recent days, with the government accusing one church leader of violating epidemic control laws.

• For the first time since mid-July, China reported no new local coronavirus cases in the western region of Xinjiang, the site of a recent outbreak. All 22 new cases reported in the Chinese mainland on Monday came from overseas.

• It’s lights out for discos and clubs in Italy. As infections in the country creep back up — especially among young people — the authorities are clamping down. In addition to ordering dancing establishments closed, they are requiring the outdoor use of masks from 6 p.m. to 6 a.m. in popular gathering spots. “We cannot nullify the sacrifices made in past months,” Italy’s health minister, Roberto Speranza, said on Facebook.

‘What convention?’ Milwaukee, site of the Democratic National Convention, copes with a gathering gone virtual.

The stretch of downtown Milwaukee where Democrats were supposed to hold their nominating convention this week was quiet and sparsely populated — another reminder of a summer lost.

Instead of thousands of Democrats preparing to gather at the newly built Fiserv Forum, there was just one street blocked off this weekend near the smaller Wisconsin Center, which will host the last few parts of the Democratic National Convention that will still take place in this city.

“What convention?” said Michaela Jaggi, a 21-year-old who passed by the Wisconsin Center on Saturday afternoon.

She eventually remembered: Joseph R. Biden Jr. was supposed to accept the Democratic nomination for president here this week.

That was before the virus crisis forced Democrats to transform their convention into a virtual event, in which none of the leading participants will appear from Milwaukee.

Some realities have not changed: The convention, which begins Monday and ends with a speech from Mr. Biden on Thursday, is the beginning of the formal general election between Mr. Biden and President Trump.

Mr. Biden’s running mate, Senator Kamala Harris of California, will have her largest audience yet, in a speech on Wednesday evening. A who’s who of Democratic Party politics will also deliver addresses to the nation — including former President Barack Obama and Senator Elizabeth Warren of Massachusetts.

The virtual nature of the convention is also a reminder that this is an election season unlike any other. Outside of Wisconsin, some states are trying novel ways to recreate at least some of the electricity of an in-person event.

A “Ridin’ with Biden” drive-in event in Massachusetts will be held on Wednesday, the day Ms. Harris and Ms. Warren are scheduled to speak. The drive-in is dedicated mostly to the state’s 140-member delegation.

In Tulsa, Okla., tickets for a drive-in watch party are $ 10 at the Admiral Twin on Thursday — the day Mr. Biden is scheduled to speak. The drive-in is largely open to the public because the state has only 43 delegates, said Alicia Andrews, the chairwoman of the Oklahoma Democratic Party.

“It’s about camaraderie,” Ms. Andrews said. “People are missing that.”

Can we have class outside today? More and more often, the answer is yes.

As school districts around the U.S. wrestle with how to bring students back to the classroom, more and more are asking a basic question: Is a room even necessary?

School officials, including in Seattle, Massachusetts and Detroit, are weighing the possibility of holding class outdoors.

Vermont, which has kept its virus cases low, appears to be in the forefront.

At the Lake Champlain Waldorf school, classes will be taught in an outdoor amphitheater, according to the NBC affiliate NECN, with heaters brought in when temperatures drop. In South Burlington, school officials are planning to put up tents, though parents can also opt for online learning.

“This is not what any of us expected, but we’re trying to use all of our creativity and ingenuity,” Amy Brennan, a community relations official at the Lake Champlain Waldorf School, told NECN.

Activists around the country are pushing for more outdoor education, according to an article in The Atlantic.

The incentive to do so during a pandemic is obvious, when proximity — especially indoors — increases the risk of virus transmission.

“It would make a huge difference if classes could be held outdoors versus indoors,” said Dr. Leana Wen, an emergency physician and public health professor who previously served as Baltimore’s health commissioner.

The approach is not without challenges. Poor weather could derail plans, and accessibility questions need to be resolved.

Dr. Ashish Jha, the director of the Harvard Global Health Institute, says that he is a “big fan” of the idea but that when he advises school districts, he tells them “not to look at this as a silver bullet.”

It does, however, offer flexibility.

“Even if you can get half the kids out, then it clears out that space for other kids to space out more indoors,” Dr. Jha said.

Some students in Denmark returned to classes with lessons held outdoors, and Italy plans to do the same.

And there are past examples: The Metro desk of The Times looked back at open-air schools in the early 1900s, when tuberculosis was surging.

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The C.D.C. begins developing a plan to distribute a coronavirus vaccine.

The Centers for Disease Control and Prevention is consulting with four states and a large city to develop plans for distributing a coronavirus vaccine, the first doses of which are expected to be available later this year or early next.

The agency chose the communities because they represent different kinds of challenges as the government prepares to begin the largest such campaign ever undertaken. The communities include small and large states, some that are doing well with their current epidemic response and at least one that is not, according to a federal official familiar with the discussions.

The states are California, Florida, Minnesota and North Dakota; the city is Philadelphia.

Each has a different demographic, ethnic makeup and population density, as well as its own infrastructure to store and deliver doses of vaccine. State and city officials are advising the C.D.C. and the Department of Defense, which are coordinating the federal response and determining how to most efficiently deliver doses of vaccine to the individuals who are most vulnerable to Covid-19, the disease caused by the virus.

Federal officials said last week that the administration expected to deliver tens of millions of vaccine doses by early 2021.

The challenges facing a nationwide vaccine campaign are enormous, including how best to store the vaccine and what kinds of clinics could handle the volume of demand. The C.D.C. reportedly favors a centralized distribution system, and the Defense Department apparently disagrees, according to the official familiar with the discussions.

Dr. Scott Gottlieb, former director of the Food and Drug Administration, said on Sunday that the government should enlist private companies to distribute a vaccine once it is developed.

“If the government tries to take physical possession of the vaccines and distribute them,” Dr. Gottlieb said on the CBS program “Face the Nation,” “that could lead to hiccups and delays in getting vaccines to the consumers. What they should be doing is directing the existing supply chain.”

Play it cool or play it safe? Scorching heat during a pandemic poses dilemmas in California.

A punishing heat wave scorching the Southwest is threatening to turn deadlier, as people struggle to keep cool in a region already plagued by wildfires and a recent surge in coronavirus cases.

With demand soaring for power to run air-conditioners, the agency that oversees California’s electric grid declared an emergency on Friday and, for the first time in 19 years, shut off service to hundreds of thousands of customers for several hours to avoid a damaging overload.

But the state’s health crisis may be deterring residents who lack air-conditioning at home from gathering at cooling centers or public places like malls and libraries. California’s cases are on the rise, with more than 65,000 new cases and about 950 related deaths over the past week.

The pandemic is “taking away one of the most critical resources for the most vulnerable,” said David Hondula, a professor who studies heat at Arizona State University. “Even in cases where facilities haven’t closed, people have to decide, ‘Do I stay home where I may be too hot, or do I go to a public or semipublic building where I may contract the virus?’ That’s a tough dilemma for folks to deal with.”

There is little relief in sight. High temperatures above 100 degrees Fahrenheit are expected in Los Angeles every day through Friday. In parts of California and Arizona, thermometers have been cracking 110. And extreme heat advisories extend to parts of Washington, Oregon, Utah and Nevada.

U.S. ROUNDUP

Democrats warn of a ‘grave threat’ to the U.S. election and demand answers from the Postal Service.

With millions of Americans expected to cast presidential ballots by mail this year because of the pandemic, congressional Democrats warned on Sunday of “a grave threat to the integrity of the election” and called on top Postal Service officials to testify before lawmakers on Capitol Hill.

The demand by top Democrats — including House Speaker Nancy Pelosi and Senator Chuck Schumer of New York — came after the Postal Service told states it might not be able to meet their deadlines for delivering last-minute mail-in ballots.

The move reflects growing alarm among Democrats and voting rights advocates about changes enacted under Louis DeJoy, the postmaster general and a Trump megadonor, that have resulted in delays in delivery and curtailed service. The changes include overtime cuts and the removal of mail-sorting machines.

“The postmaster general and top Postal Service leadership must answer to the Congress and the American people as to why they are pushing these dangerous new policies that threaten to silence the voices of millions, just months before the election,” the lawmakers said on Sunday.

Ms. Pelosi is calling the House back from its annual summer recess to consider a Postal Service bill as soon as Saturday, according to a senior Democratic aide familiar with the plans. Mr. Schumer demanded on Sunday that Senator Mitch McConnell, Republican of Kentucky and the majority leader, bring senators back to Capitol Hill to take up the House measure.

In addition, Democratic state attorneys general said Sunday that they were exploring legal action against the cutbacks and changes at the Postal Service. Washington State is expected to be the first to file this week, and Pennsylvania and New York are likely to follow, according to two people with knowledge of the discussions.

Mark Meadows, the White House chief of staff, said on Sunday that the administration would be open to a measure that would provide supplemental funding to help the Postal Service handle a surge in mail-in ballots.

In other developments around the U.S.:

• Under emergency coronavirus orders, the Trump administration is using hotels across the country to hold migrant children and families before expelling them. Government data obtained by The New York Times, along with court documents, show that hotel detentions overseen by a private security company have ballooned in recent months under an aggressive border closure policy related to the pandemic.

• Nursing homes have been a center of America’s virus outbreak, with more than 62,000 residents and staff members dying from Covid-19 at such homes and other long-term care facilities — about 40 percent of the country’s virus fatalities. Now, the lightly regulated industry is campaigning in Washington for federal help that could increase its profits.

• With New York State’s virus infections at a fraction of the levels they reached during a devastating spring, the effort to prevent a resurgence includes a 14-day quarantine for travelers entering New York from states where positive test results for the virus exceed 10 percent. But in the absence of broad enforcement, many travelers to New York seem to be making their own rules, and social media has been capturing the exploits of these quarantine scofflaws.

• The C.D.C. issued updated guidance on coronavirus infections in children, after recent reports that cases among that group surged last month. Those reports come as states across the country are trying to reopen schools safely. Georgia announced on Sunday that it would switch to online instruction two days a week after reporting at least nine cases among students. However, it remains unclear how susceptible children are to the virus compared with adults, as well as how transmissible Covid-19 is among them or to adults.

• On Sunday, the U.S. reported more than 42,300 new cases and more than 510 new deaths.

A rural U.S. county has a jump in virus cases as a university reopens.

Story County, in the dead center of Iowa, is mostly farmland, with only about 90,000 residents. But it has seen its coronavirus case count shoot up almost 30 percent, or at least 308 cases, just in the last two weeks.

What happened?

Iowa State University, in Ames, reopened.

At least 141 of those new cases are students who were tested as they moved into residence halls or campus apartments for the fall semester. The university said it had tested 6,500 students, using its veterinary diagnostic lab to process the tests and get results back quickly, usually within 24 hours.

That is still only a portion of the student body, which numbered nearly 33,400 students last year. Many students living in sorority or fraternity houses or in off-campus apartments, for example, may not have been included.

Students who test positive are moved to “isolation rooms” on campus, and their recent contacts are notified. Other students living in university housing who may have been exposed to them are given quarantine rooms and monitored for symptoms.

“We understand that receiving news that you need to isolate or quarantine is stressful for our students and families, especially when this impacts participation in campus events and classes,” Erin Baldwin, the interim senior vice president for student affairs at the university, said in a statement on Friday, adding that the school would “provide flexibility while they navigate coursework virtually.”

The increase in virus cases comes as Ames and the rest of Story County work to recover from an unusual type of severe windstorm, known as a derecho, that wreaked havoc across much of the Midwest last week.

“We are acutely aware that as many as 1,200 Ames customers remain without electricity five days after the storm,” Mayor John Haila said in a statement late Saturday. He said the city had opened cooling centers and had distributed ice to residents without power.

Reporting was contributed by Nicholas Bogel-Burroughs, Ben Carey, Chris Cameron, Damien Cave, Choe Sang-Hun, Emily Cochrane, Monica Davey, Melina Delkic, Caitlin Dickerson, Ben Dooley, Jesse Drucker, Catie Edmondson, Reid J. Epstein, Hailey Fuchs, Abby Goodnough, Rebecca Halleck, Astead W. Herndon, Jan Hoffman, Annie Karni, Alyson Krueger, Christina Morales, Eric Nagourney, Aimee Ortiz, Bryan Pietsch, Jessica Silver-Greenberg, Lucy Tompkins, Will Wright and Katherine J. Wu.