U.S. Races to Vaccinate as Variants Threaten to Produce Surge in Cases
After weeks of decline followed by a plateau, the nation is seeing a rise in coronavirus cases again. Here’s the latest on Covid-19.,
Even as the United States steps up the pace of vaccinations, it remains in a race against a virus that is on the upswing as the spread of worrisome variants and a loosening of restrictions threatens to produce a possible surge in new infections.
After weeks of decline followed by a plateau, coronavirus cases seem to be rising again in the United States. As of Monday, there have been an average of more than 65,000 cases a day over the past two weeks. That is nearly a 19 percent rise over the daily average two weeks earlier, according to a New York Times database. Deaths have been hovering around 1,000 a day in recent weeks.
Similar upticks in the past have led to major surges in the spread of the virus. Still, new cases and deaths have declined from the early January peak. The seven-day average of new deaths remains near 1,000 a day.
Federal health officials are pleading with Americans to stay vigilant, warning of a potential fourth surge as some states, like Texas and Florida, relax or eliminate virus restrictions. They are also concerned about variants like the one that walloped Britain, called B.1.1.7, which has led to a new wave of cases across most of Europe. The United States remains behind in its attempts to track them, though the Centers for Disease Control and Prevention’s efforts to locate them has recently improved and will continue to grow.
President Biden on Monday called for governors and mayors to maintain or reinstate mask mandates and warned against “letting up on precautions” before the virus is more under control.
“We are giving up hard-fought, hard-won gains,” he said. Key members of Mr. Biden’s virus team had been expected to raise the issue during a weekly call with governors on Tuesday.
Some scientists predicted weeks ago that the number of infections could curve upward again in late March, at least in part because of the rise of variants of the coronavirus across the country. The B.1.1.7 variant isrising exponentially in Florida where it accounts for a greater proportion of total cases than in any other state, according to numbers collected by the C.D.C.
More Americans are traveling as well. Over the last week, an average of 1.3 million people passed through security checkpoints at U.S. airports each day, according to the Transportation Security Administration. On Sunday alone, more than 1.5 million people went through T.S.A. screenings — a sharp increase from 180,000 on the same date in 2020.
Hours ahead of Mr. Biden’s warnings on Monday, Dr. Walensky was emotional as she spoke during a news briefing. She said that while the nation had “so much reason for hope,” she could not shake the recurring feeling of “impending doom.”
“I think people want to be done with this,” she said. But now, she said, “we actually have it in our power to be done, with the scale of the vaccination. And that will be so much slower if we have another surge to deal with as well.”
Dr. Walensky’s remarks came at a striking moment when there has been optimism about the availability and effectiveness of vaccines. Three dozen states are set to open eligibility to the general public by mid-April, well before Mr. Biden’s earlier pledge of May 1.
More than one in three American adults have received at least one shot and nearly one-fifth are fully vaccinated, but the nation is a long way from reaching so-called herd immunity, the tipping point that comes when the spread of a virus begins to slow because enough people, estimated at 70 to 90 percent of the population, are immune to it.
The country’s current situation harks back to the early days of the pandemic, “where we had introductions of virus to different places that scientists warned would be a problem,” said Bill Hanage, an epidemiologist at the Harvard T.H. School of Public Health. “People waited for them to be a problem before they took action — and then too late, they took action.”
Apoorva Mandavilli contributed reporting.
BRUSSELS — Citing what they call “the biggest challenge to the global community since the 1940s,” the leaders of more than two dozen countries, the European Union and the World Health Organization on Tuesday floated an international treaty to protect the world from pandemics.
In a joint article published in numerous newspapers across the globe, the leaders warn that the current coronavirus pandemic will inevitably be followed by others at some point. They outline a treaty meant to provide universal and equitable access to vaccines, medicines and diagnostics, a suggestion first made in November by Charles Michel, the president of the European Council, the body that represents the leaders of the European Union countries.
The article argues that an international understanding similar to the one that followed World War II and that led to the United Nations is needed to build cross-border cooperation before the next global health crisis upends economies and lives. The current pandemic is “a stark and painful reminder that nobody is safe until everyone is safe,” the leaders write.
The suggested treaty is an acknowledgment that the current system of international health institutions, symbolized by the relatively powerless World Health Organization, an agency of the United Nations, is inadequate to the problem.
“There will be other pandemics and other major health emergencies. No single government or multilateral agency can address this threat alone,” the leaders note. “We believe that nations should work together toward a new international treaty for pandemic preparedness and response.”
The treaty would call for better alert systems, data sharing, research and the production and distribution of vaccines, medicines, diagnostics and personal protective equipment, they said.
“At a time when Covid-19 has exploited our weaknesses and divisions, we must seize this opportunity and come together as a global community for peaceful cooperation that extends beyond this crisis,” the leaders write. “Building our capacities and systems to do this will take time and require a sustained political, financial and societal commitment over many years.”
The article is not clear, however, about what would happen should a country choose not to cooperate fully or to delay sharing scientific information, as China has been accused of doing with the W.H.O.
China has not signed the letter, at least so far. Neither has the United States.
In a news conference on Tuesday in Geneva, the director general of the World Health Organization, Tedros Adhanom Ghebreyesus, said that when discussions on a treaty start, “all member states will be represented.”
Asked if the leaders of China, the United States and Russia had been asked to sign the letter, he said that some leaders had chosen to “opt in.”
“Comment from member states, including the United States and China, was actually positive,” he said. “Next steps will be to involve all countries, and this is normal,” he added. “I don’t want it to be seen as a problem.”
As well as European countries and the W.H.O., the letter’s signatories included nations in Africa, Asia and Latin America.
New York can begin vaccinating anyone 30 or older on Tuesday and will make all residents 16 or over eligible on April 6, beating President Biden’s goal of making every adult eligible for a coronavirus vaccine by May 1, Gov. Andrew M. Cuomo announced on Monday.
New York was one of only a few states that had not yet set a timeline for universal adult eligibility. Five states had already expanded eligibility fully by the end of last week; six did so on Monday; seven more will follow later this week, and another six on April 5. At least 11 states have said they will wait until May 1.
Though Mr. Cuomo has gradually loosened vaccine eligibility criteria over the last month, he expressed reluctance last week to set a specific target date for doing away with the state’s requirements. The governor said he did not want to outline a timeline for more widespread vaccination until he was more confident that New York would have adequate vaccine supply on hand for its population.
“I just want to make sure that the allocation projections that we’re getting from the feds are right, frankly,” Mr. Cuomo said at a news conference last week. “I don’t want to say, ‘We’re going to open up to 30-year-olds in three weeks,’ and then something happens with the allocation.”
Mr. Cuomo’s announcement comes as New York has been adding new virus cases at one of the highest rates among U.S. states. As of Monday, the state had a seven-day average of 49 new virus cases a day for every 100,000 residents, according to a New York Times database, second only to New Jersey. (The nation as a whole was averaging 19 new cases per 100,000 people.)
Even as the number of new cases continues to mount, the state has not faced anywhere near the level of devastation that it experienced a year ago, when hospitals were overwhelmed with patients and morgues were overflowing.
Buoyed by its vaccination progress, the state has also been gradually reopening businesses in the last several weeks. Mr. Cuomo allowed sporting events and concerts to resume at large venues last month and movie theaters to bring back audiences this month. Restaurants in New York City are now allowed to serve diners indoors at 50 percent capacity, their highest level of indoor dining since Mr. Cuomo closed them last year at the onset of the pandemic.
As of Monday morning, 29.6 percent of people in New York State had received at least one shot of a vaccine, while 16.8 percent were fully vaccinated, according to the state’s data.
Currently, all people 50 and over are eligible to receive the vaccine in New York, in addition to teachers, some essential workers and people with certain medical conditions that make them more susceptible to serious illness from the virus.
As the coronavirus forces a realignment of how people live and work, Ireland is hoping to use the moment to help struggling small towns and villages to narrow the ever-widening gap with urban centers.
The Irish government announced this week that it was prepared to spend about $1 billion to encourage people to settle in rural areas, hoping that an investment in revitalizing town centers and other incentives will lure back younger people who have for years flocked to cities, particularly Dublin.
Like other countries across Europe, the hollowing out of once vibrant villages and small towns has contributed to wider social divisions, and scholars and public policy experts have warned that the split could become a major source of tension in Western democracies.
Ireland’s proposal, “Our Rural Future,” is one of the most ambitious efforts announced in Europe to address the issue, prompted by the changes brought about by the pandemic.
Among other things, it proposes legislation that would give employees the right to request to work from home, the establishment of a network of 400 remote-working hubs, and funding for better internet connectivity nationally.
Nearly half of people in Ireland live in rural areas and small towns, but the government hopes that the proposals will lift that number.
Announcing the plan, the prime minister, Micheal Martin, said, “Ireland is heading into an era of unprecedented change, and with that comes unprecedented opportunity.”
“Over the course of the pandemic, we have discovered new ways of working and we have rediscovered our communities,” he added.
Dublin has long been a magnet for the country’s nearly five million residents, and the capital’s thriving tech hub has only made the city more desirable in recent years, particularly for younger workers.
But a shift to remote work during the pandemic, which many experts agree is likely to continue in some capacity even after the pandemic recedes, has provided an opportunity for a rethink, the government said.
The proposals announced on Monday could also have the downstream effect of easing a deep housing crisis in Dublin, where small supply and high demand have seen prices skyrocket in recent years.
Many retail and fast-food workers in states like Mississippi and Texas, where governments have removed mask mandates before a majority of people have been vaccinated and while troubling new variants of the coronavirus are appearing, are feeling a heightened anxiety.
It feels like a return to the early days of the pandemic, when businesses said customers must wear masks but there was no legal requirement and numerous shoppers refused. Many workers say that their stores do not enforce the requirement, and that if they approach customers, they risk verbal or physical altercations.
For many who work in retail, especially grocery stores and big-box chains, the mask repeals are another example of how little protection and appreciation they have received during the pandemic.
While they were praised as essential workers, that rarely translated into extra pay on top of their low wages. Grocery employees were not initially given priority for vaccinations in most states, even as health experts cautioned the public to limit time in grocery stores because of the new virus variants. (Texas opened availability to everyone 16 and older on Monday.)
The issue has gained prominence: On Monday, President Biden called on governors and mayors to maintain or reinstate orders to wear masks as the nation grapples with a potential rise in cases.
The United Food and Commercial Workers union, which represents nearly 900,000 grocery workers, said this month that at least 34,700 grocery workers around the country had contracted or been exposed to Covid-19 and that at least 155 workers had died.
The recent mass shooting at a grocery store in Boulder, Colo., has only rattled workers further and added to concerns about their own safety.
A Kroger representative said that the chain would “continue to require everyone in our stores across the country to wear masks until all our frontline grocery associates can receive the Covid-19 vaccine,” and that it was offering one-time payments of $100 to workers who received the vaccine.
The differing state and business mandates have some workers worried about more confrontations. The retail industry was already trying to address the issue last fall, when a major trade group helped put together training to help workers manage and de-escalate conflicts with customers.
As England took its first step on Monday toward lifting a national lockdown, one piece of news seemed to capture the mood of optimism: just before the regulations were eased, there had been a day with no recorded Covid deaths in London.
The figure for Saturday proved to be not quite the hoped-for zero (another metric recorded two deaths that day and a single death on Sunday), but that did little to dampen the sense that the country was turning a corner.
With the vaccination campaign chugging along — and nearly everyone over the age of 50 now offered at least a first shot — many Britons have started to dare to look forward to the reopening of nonessential services and the return of outdoor dining at restaurants and pubs, scheduled to happen on April 12.
Helped by clear spring skies in the capital on Tuesday, there were signs that the city was edging back to life after a long hibernation. Stores raised shutters and laid out goods in windows. Restaurants set out chairs. Traffic along the Thames was picking up, with the ferries starting to carry passengers.
And in parks across the city, people gathered to bat around a ball, socialize with friends or simply bask in the sun.
Still, the anticipation that the worst of the pandemic could be over was tempered by warnings from officials that, with many European countries in the grip of a fresh wave of cases, the lull in Britain could be short-lived.
Prime Minister Boris Johnson said, “What we don’t know is exactly how strong our fortifications are.”
“Historically, there’s been a time lag,” he added, “and then we’ve had a wave ourselves.”
Vaccinations have helped create a wall against new infections, and that protection would strengthen with the second dose, according to England’s chief medical officer, Chris Whitty, on Monday.
But, he added, it was a “leaky wall.”
Vermont is reporting a sharp spike in coronavirus cases, reaching highs that have not been seen since January.
“This is a concerning number of new cases and should not be dismissed,” Dr. Mark Levine, the state’s health commissioner, said at a news conference on Friday.
Vermont hit a single-day case record with 283 new confirmed cases on Friday, according to a New York Times database, making it the first state to set a case record since Jan. 18. (Its seven-day average, 154, is still lower than its peak in January.) Half of the cases reported in the past two weeks were in people under the age of 30, officials said.
The renewed surge has been driven by a number of factors, including pandemic fatigue and the spread of worrisome variants, Dr. Levine said in an interview on Monday. As older people get vaccinated and deaths start to drop, younger people have been more willing to gather in groups, he said.
The University of Vermont has reported a significant increase in confirmed cases among students, climbing to 80 last week from 41 two weeks before. The statewide surge, though, does not appear to be driven largely by college students, Dr. Levine said, since there have not been widespread increases on other campuses.
Cases across the United States have started to rise in recent weeks, after infections began to drop following a post-holiday surge. Scientists have warned for weeks about another increase, as more cases of variants are detected and states lift restrictions. Still, the United States remains behind in its attempts to track variants, though the Centers for Disease Control and Prevention’s efforts to locate them has recently improved and will continue to grow. States in the Northeast have accounted for about 30 percent of the nation’s new cases over the past two weeks, up from 20 percent in early February.
Still, Vermont state officials defended the recent lifting of restrictions, citing a continued drop in deaths and hospitalizations. The state loosened restrictions last week, reopening bars at a limited capacity and allowing restaurants to seat up to six people from different households together. The state still has a mask mandate.
Anne Sosin, a policy fellow at Dartmouth College who has been tracking Vermont’s Covid-19 response since the pandemic’s start, said the lifting of restrictions combined with the spread of new variants could be dangerous. “If we create the conditions for transmission, variants will just exacerbate the impacts of that,” she said.
Vermont opened vaccinations to adults ages 50 and older on Monday, and will expand eligibility to all adults on April 19. About 33 percent of the state’s population has received at least one dose, according to a New York Times vaccine tracker.
“Now that we have a timeline for all Vermonters to get vaccinated, mark your calendar, make your appointment and get your shot,” Dr. Levine said on Friday.
— Madeleine Ngo
The coronavirus vaccines made by Moderna and Pfizer-BioNTech are proving highly effective at preventing symptomatic and asymptomatic infections under real-world conditions, federal health researchers reported on Monday.
Consistent with clinical trial data, a two-dose regimen prevented 90 percent of infections by two weeks after the second shot. One dose prevented 80 percent of infections by two weeks after vaccination.
The news arrives even as the nation rapidly broadens eligibility for vaccines, and the average number of daily shots continues to rise. The seven-day average of vaccines administered hit 2.76 million on Monday, an increase over the pace the previous week, according to the Centers for Disease Control and Prevention.
But the virus may be gaining renewed momentum. According to a New York Times database, the seven-day average of new virus cases as of Sunday was 63,000, an increase of more than 16 percent over the past two weeks.
Similar upticks over the summer and winter led to major surges in the spread of disease, Dr. Rochelle Walensky, director of the Centers for Disease Control and Prevention, said at a news briefing on Monday. She said she had a sense of “impending doom” about a possible fourth surge of the virus.
The nation has “so much reason for hope,” she said. “But right now I’m scared.”
Scientists have debated whether vaccinated people may still get asymptomatic infections and transmit the virus to others. The new study, by researchers at the C.D.C., suggested that since infections were so rare, transmission was likely rare, too.
There also has been concern that variants may render the vaccines less effective. The study’s results do not confirm that fear. Troubling variants were circulating during the time of the study — from Dec. 14, 2020, to March 13, 2021 — yet the vaccines still provided powerful protection.
The C.D.C. enrolled 3,950 people at high risk of being exposed to the virus because they were health care workers, first responders or others on the front lines. None had previously been infected.
Most participants — 62.8 percent — received both shots of the vaccine during the study period, and 12.1 percent had one shot. They collected their own nasal swabs each week, which were sent to a central location for P.C.R. testing, the most accurate type of test. The weekly swabs allowed the researchers to detect asymptomatic infections as well as symptomatic ones.
The investigators asked participants about symptoms associated with infection, including fever, chills, cough, shortness of breath, sore throat, diarrhea, muscle aches, or loss of smell or taste. They also analyzed patients’ medical records to detect illnesses.
Fifty-eight percent of the infections were detected before people had symptoms. Just 10.2 percent of infected people never developed symptoms.
Among those who were fully vaccinated, there were .04 infections per 1,000 person-days, meaning that among 1,000 persons there would be .04 infections in a day.
There were 0.19 infections per 1,000 person-days among those who had had one dose of the vaccine. In contrast, there were 1.38 infections per 1,000 person-days in unvaccinated people.
Dr. Walensky urged Americans to continue taking precautions and to waste no time getting the shots as soon as they are eligible.
“I am asking you to just hold on a little longer, to get vaccinated when you can, so that all of those people that we all love will still be here when this pandemic ends,” she said.
A fresh surge of new coronavirus cases is taking a heavy toll in Pakistan, with Prime Minister Imran Khan and President Arif Alvi among several senior officials to have contracted the virus recently, just as the nation struggles to stem the outbreak.
As the number of cases soars, the federal government has imposed a ban on public gatherings, sports events and wedding ceremonies, starting in April.
Emergency wards of hospitals in Lahore and Islamabad have been filled to capacity with coronavirus patients, according to health workers. Several neighborhoods in both cities have been placed under strict lockdowns.
Officials said on Tuesday that at least 100 deaths had been reported in the past 24 hours. The country has recorded 14,356 deaths and 663,200 infections since the start of the pandemic.
The virus is also taking a toll in the senior ranks of the government. Mr. Khan was reported on March 20 to have become infected, while Mr. Alvi and the defense minister, Pervez Khattak, tested positive on Monday.
The president’s wife, Samina Alvi, who said she had tested negative, noted that the couple had received a first vaccine dose in mid-March, although it was not clear which vaccine.
“It takes time to develop immunity,” she wrote on Twitter.
Officials said that Mr. Khan was making a steady recovery and had been allowed to resume work.
On Tuesday, Abdul Hafeez Sheikh, the country’s former finance minister, also tested positive for the coronavirus. Mr. Khan removed him from his position on Monday because of Mr. Sheikh’s failure to stem an increasing inflation rate.
Dr. Faisal Sultan, the acting health minister, said that the four provinces of Pakistan had been given permission to independently import vaccines.
The federal government has said that it is in the process of procuring more vaccines from China, but critics have denounced the slow rollout. The vaccination drive was started this month, with people over the age of 60 and health workers eligible for doses developed by the Chinese company Sinopharm.
The German health authority responsible for vaccine guidelines recommended on Tuesday that the country suspend use of the AstraZeneca vaccine in adults under 60 because of concerns about a possible association with blood clots. The action came a day after Canada suspended its use in people 55 and under.
Earlier in the day, a number of local authorities in Germany — including Berlin, Munich and the state of Brandenburg — had made similar moves.
A small district in North Rhine-Westphalia banned use of the AstraZeneca vaccine on Monday for all women below the age of 55, after serious episodes last week involving two women who had received the vaccine: one, 47, died of sinus vein thrombosis and another, 28, became seriously ill.
No causative link has been established between the patients’ conditions and the vaccine.
Chancellor Angela Merkel was scheduled to meet Tuesday evening with state governors to discuss the AstraZeneca vaccine. The commission responsible for vaccination recommendations will meet again on Thursday to finalize its decision.
France and several Nordic countries have also taken a precautionary stance on the vaccine, even after the European Union’s top drug regulator cleared it as safe this month. Some suspensions in Europe may have been driven as much by political considerations as by science.
In Canada, Dr. Caroline Quach-Thanh, the chairwoman of the National Advisory Committee on Immunization, said at a video news conference on Monday that more study was needed. “Given alternative vaccines are available in Canada, N.A.C.I. feels it is very important to study the risks and benefit as a precautionary measure,” she noted.
The Canadian decision was made after reviewing evidence emerging from Germany, where the Paul-Ehrlich Institut, the country’s vaccine regulatory body, reported earlier this month that at least seven people who had recently received the AstraZeneca vaccine had developed a very rare, potentially fatal condition involving blood clots that can block the drainage of blood from the brain, associated with low blood platelet counts (thrombocytopenia) and bleeding.
(An earlier version of this item referred incompletely to the condition.)
Statistically, seven cases was significantly higher than normal for the population of 1.6 million adults that had received the vaccine in Germany by March 15, the institute said; by its calculations, just one case would have been expected.
The Canadian health authority continues to recommend the AstraZeneca vaccine for older adults, who are much more susceptible than younger people to serious cases of Covid-19, and have not appeared to develop blood clots in studies conducted in Europe, the committee members said.
“We want to prevent hospitalizations and severe disease for those over 55,” Dr. Quach-Thanh said.
The AstraZeneca vaccine, created by Oxford University, was approved in late February for use in Canada but has suffered setbacks there and elsewhere. Soon after its approval, N.A.C.I. recommended that it not be administered to people 65 and older, because of a lack of data about that age group; two weeks later, N.A.C.I. waived its initial concerns and approved the vaccine for all adults.
The vaccine was the third approved in the country, after those from Pfizer-BioNTech and Moderna. Just over 300,000, or 6 percent, of the doses administered in Canada so far have been AstraZeneca’s vaccine. The Biden administration promised this month to loan Canada 1.5 million more doses of the vaccine, which still has not been approved for use in the United States.
Massachusetts on Monday expanded a new state-financed coronavirus testing program to allow every public school in the state to test all students and staff members weekly for the rest of the school year, using a pooled testing approach that could be a model for school districts nationwide.
More than 1,000 schools in Massachusetts, representing nearly half the districts in the state, are already participating in the program.
Since February, the program has analyzed 22,679 pooled samples from students, teachers and staff members, reporting on Monday a positivity rate of less than 1 percent, considered low. Since the pooled samples typically include swabs from seven different people, state officials said the individual positivity rate is probably much lower.
In a phone interview on Monday, Gov. Charlie Baker said that the state had been able to scale up the program by vetting testing labs and signing contracts with them, instead of leaving each district to do that work on its own. He estimated that the program, which is using federal Covid relief funds to pay for the tests, could cost $30 million to $40 million.
“We started doing it on a demonstration basis with a few school districts just to test it and see if the logistics could work,” Mr. Baker said. “We now have a working model that is operating at a pretty big scale and in a pretty big state.”
The pooled testing program collects nasal swabs from students, faculty and staff members and then tests them in batches, a process that saves time and lab resources. Last week, about 63,000 students and staff members were tested.
If a batch tests negative, everyone in the pool is considered to have a negative result. If a batch tests positive, each person in the pool is then tested.
Massachusetts, which had initially planned to pay for the tests for schools until mid-April, now plans to cover the costs through the end of the school year. It is also encouraging other school districts in the state to sign up.
Mr. Baker said he planned to promote the Massachusetts model to other states. Some districts, like Montgomery County Public Schools, Maryland’s largest system, are planning to introduce pooled testing in April.
“There’s enough money in the various federal bills that have been passed, including the most recent one, to make it possible for states or municipalities both to pay for a program like this,” Mr. Baker said.
A World Health Organization report on the provenance of the coronavirus pandemic, released on Tuesday, has raised more questions than answers around the globe, including some from the W.H.O. director-general, Dr. Tedros Adhanom Ghebreyesus, who said he hoped future studies would include “more timely and comprehensive data sharing.”
Determining the origin of the virus could help prevent another pandemic and aid in the development of vaccines and treatments.
Here is what the Times knows about the report.
The experts dismissed a lab leak theory. For months, scientists, politicians and others outside China have promoted the theory that the virus might have emerged after a laboratory accident in China. The experts called the theory “extremely unlikely,” after they spoke with scientists at the Wuhan Institute of Virology, which houses a state-of-the-art laboratory known for its research on bat coronaviruses.
Officials there assured the investigators that they were not handling any viruses that appeared to be closely related to the coronavirus that caused the recent pandemic, according to meeting notes included in the report. They also said that staff members had been trained in security protocols.
The role of animal markets is still unclear. The expert team concluded that the coronavirus probably emerged in bats before spreading to humans through an intermediate animal, but they said there is no firm conclusion for that theory. Early in the pandemic, Chinese officials floated theories suggesting that the coronavirus outbreak might have started at the Huanan market. More than a year later, the role of animal markets in the story of the pandemic is still unclear, according to the report.
The inquiry’s success will depend on China. The expert team offers a long list of recommendations for additional research: more testing of wildlife and livestock in China and Southeast Asia, more studies on the earliest cases of Covid-19 and more tracing of pathways from farms to markets in Wuhan. But it is unclear whether China, which has repeatedly hindered the W.H.O. inquiry, will cooperate. It took months for the country to allow a team from the global health agency to visit.