In documents released Tuesday morning, Moderna argued that the Food and Drug Administration should authorize a half-dose of its coronavirus vaccine as a booster shot for recipients at least six months after the second dose, citing evidence that the vaccine’s potency against infection wanes over time. The agency noted in its own analysis that, overall, available data show Moderna and the other vaccines “still afford protection against severe Covid-19 disease and death in the United States.”
Moderna cited the rate of breakthrough infections, “real world evidence of reduced effectiveness against the Delta variant,” and falling levels of neutralizing antibodies from its vaccine six to eight months after a second dose. The company said its clinical trial studies showed that a third injection boosted antibody levels — one measure of the immune system’s response — higher than what they had been before the second dose.
The documents were released by the F.D.A. ahead of a two-day meeting of the agency’s advisory committee, scheduled for Thursday and Friday. In its own briefing document for the committee, also released Tuesday, the F.D.A. summarized the data without taking a position.
The committee is expected to vote on whether to recommend emergency authorization of boosters of Moderna’s and Johnson & Johnson’s vaccines. While the panel’s votes are not binding, regulators typically follow them.
Moderna did not try to argue that its vaccine is waning now against severe disease or hospitalization, and the existing data does not appear to support that claim. That distinguishes Moderna’s application from Pfizer-BioNTech’s last month.
In its document, the F.D.A. said: “Some real world effectiveness studies have suggested declining efficacy of Moderna Covid-19 vaccine over time against symptomatic infection or against the Delta variant, while others have not.”
The agency said “there are many potentially relevant studies” and it has not independently reviewed the underlying data or conclusions of each one.
The F.D.A. and the Centers for Disease Control and Prevention decided to authorize boosters for many but not all Pfizer-BioNTech vaccine recipients. The eligible include those 65 or older, who live in long-term care facilities, have underlying medical conditions or are at higher risk of exposure to the virus because of their jobs or institutional settings. The last group includes health care workers, teachers and prisoners.
In the document released Tuesday, the F.D.A. proposed the outside experts consider essentially the same eligibility groups for Moderna recipients. But people familiar with the deliberations said that federal officials may also ask the committee to consider broadening eligibility for boosters of both vaccines to include more middle-aged people.
Moderna said it compared using a full dose and a half dose as a booster, and found that a half dose boosted antibody levels well with lower risks of adverse side effects. It also tried to make a point about conserving limited supplies, saying a half-dose “would result in a substantial increase in the world wide supply” of its vaccine.
Several independent studies have tried to estimate how long Moderna’s two-dose vaccine remains effective against mild, moderate and severe Covid. One looked at Covid cases last summer among more than 15,000 volunteers in Moderna’s clinical trial, some of whom had been vaccinated a full year earlier. Researchers compared Covid cases in July and August among trial participants who had been fully vaccinated between July and October 2020 with cases among those who were fully vaccinated between December 2020 and March 2021.
Those who got vaccinated later had a 36 percent lower rate of disease. But Dr. Hana M. El Sahly, a professor of molecular virology at Baylor College of Medicine and one of the lead researchers, said the study did not find a statistically significant difference between the two groups in cases of severe Covid — of which there were only 19.
Overall, she said, “the findings do not indicate that a booster is needed.” The study was backed by the National Institutes of Health, researchers said.
Another recent C.D.C. study reviewed case files of nearly 3,700 patients in 21 different hospitals from March to August. Researchers found that of the three vaccines available in the United States, Moderna’s vaccine held up best over six months.
The researchers said that Moderna was 93 percent effective against hospitalization, compared with 88 percent for Pfizer and 71 percent for Johnson & Johnson. Pfizer’s efficacy dropped significantly after four months, to 77 percent, while Moderna’s basically held steady, they said.
Given the dearth of data showing that Moderna’s protection weakens against severe disease, the committee’s deliberations about boosters for Moderna recipients will likely revolve around other key questions.
First, is there a need to “harmonize” U.S. booster strategy, making recipients of all three vaccines eligible even if they keep their potency for different periods of time? Some federal officials argue that with many Pfizer recipients already receiving boosters, the answer is yes.
“We’re in this very complicated situation right now: People are going into pharmacies or places where vaccines are available and saying, ‘I want my third dose of Moderna, or I want my second dose of J.&J.,” said Dr. H. Cody Meissner, an infectious disease expert at Tufts Medical Center who serves on the F.D.A. panel. “I don’t think anyone has much doubt that we will need a booster dose for these vaccines. What we don’t know is: How urgent is the need?”
Another question is whether Moderna will eventually wane against severe disease. Some booster advocates argue that Moderna is following the same path as Pfizer’s vaccine, just more slowly, because its initial dosage is significantly stronger and the interval between the first two shots is longer.
Committee members are also expected to debate whether Moderna recipients should be given a booster simply to protect them against the risk of mild or moderate disease, or to try to disrupt transmission of the virus.
“The fundamental issue is, what are we trying to do?” said Dr. El Sahly. “Both Moderna and Pfizer seem to have waned when it comes to mild to moderate disease, especially with the Delta variant.
“So, if that’s the goal, a booster is needed. If we want to prevent only severe disease that lands people in the hospital, that’s a different mathematics.”
Britain’s initial response to the Covid-19 pandemic “ranks as one of the most important public health failures the United Kingdom has ever experienced,” a parliamentary inquiry has found, blaming the British government for “many thousands of deaths which could have been avoided.”
In a highly critical, 151-page report, two committees of lawmakers wrote that the government’s failure to carry out widespread testing or swiftly impose lockdowns and other restrictions amounted to a pursuit of “herd immunity by infection” — accepting that many people would get the coronavirus and that the only option was to try to manage its spread.
“It is now clear that this was the wrong policy, and that it led to a higher initial death toll than would have resulted from a more emphatic early policy,” the report concluded.
Although many of its findings were already known, the report grew out of the first authoritative investigation of Britain’s pandemic response. The inquiry, led by lawmakers from Prime Minister Boris Johnson’s own Conservative Party, described a litany of failures by his government in the months after the first coronavirus cases were detected in Britain in January 2020.
Britain has experienced one of the worst Covid-19 outbreaks among wealthy nations, with 162,000 deaths officially attributed to the disease. Like many Western democracies, at the outset of the pandemic it struggled to balance individual liberties with strict measures such as lockdowns, and suffered from mismanagement at the top levels of government.
The country has tried to put those missteps behind it, racing ahead last winter and spring as one of the world leaders in vaccinations, with more than three-quarters of people 12 and older having now received two doses of a Covid vaccine. As deaths declined from prior peaks, Britain cast off nearly all restrictions, and even though infections remain high, Mr. Johnson has tried to portray the country as having put the worst of the pandemic behind it.
But as he struggles against a raft of new economic problems, the report renewed criticisms of his government’s handling of the virus. It does not require the government to act, but its findings are likely to influence the public debate for months to come. A full public inquiry promised by Mr. Johnson is not scheduled to begin until next year.
“This report lays bare the failings of the U.K. government to contain Covid, including delayed border measures, nonexistent testing for weeks, lack of P.P.E. for frontline workers and a late lockdown,” said Devi Sridhar, the head of the global public health program at the University of Edinburgh. “Hopefully, lessons will be learned from this.”
Gov. Greg Abbott of Texas issued a broad executive order on Monday that bars virtually any coronavirus vaccine mandate in the state.
Mr. Abbott, a Republican, has been among the most vocal political leaders in the United States opposing vaccine mandates. His latest executive order includes private employers, which had been exempt from previous edicts against the mandates.
“No entity in Texas can compel receipt of a Covid-19 vaccine by any individual, including an employee or a consumer, who objects to such vaccination for any reason of personal conscience, based on a religious belief, or for medical reasons, including prior recovery from Covid-19,” the order states. “I hereby suspend all relevant statutes to the extent necessary to enforce this prohibition.”
The order acknowledges that “vaccines are strongly encouraged for those eligible to receive one, but must always be voluntary for Texans.”
Shortly after that order was signed, Facebook, which employs more than 2,000 people in the state, said in a statement it was reviewing the order “and our company vaccine policy currently remains unchanged.”
Professor Srividhya Ragavan, who teaches global public health at Texas A&M University School of Law, said the order will probably be litigated in court, as Mr. Abbott’s ban on mask mandates has been.
Courts in the United States have a long history of upholding vaccine mandates, Professor Ragavan said, in part, because people who oppose such mandates are not the only individuals whose rights the courts take into account.
“I may choose not to get treatment for cancer,” Ms. Ragavan said, “but when it’s a case of an infectious disease, your freedom has the ability to affect someone else.”
The order may be hard to enforce because of its broad scope and timing, said Josh Blackman, a constitutional law professor at South Texas College of Law Houston. Companies that operate in multiple states will have to wrestle with whether it applies to them merely by having some operations in Texas, he said.
Some businesses may face “severe financial risk” if they already have mandates in place, said Mr. Blackman.
The order ratchets up an already deeply polarizing debate. On one side is President Biden, who has mandated shots for health care workers, federal contractors and the vast majority of federal workers, and has ordered all private employers with 100 workers or more to require their workers to be vaccinated or undergo frequent testing.
Mr. Biden’s actions reflected growing frustration with the millions of Americans who are eligible for shots but have not gotten them. In announcing them, he spoke of the need to “protect vaccinated workers from the unvaccinated.”
As of Friday, 66 percent of people 12 and older in the United States have been fully vaccinated, according to a New York Times database — a lower figure than dozens of other countries have achieved.
On the other side are the Republican governors of Texas, Florida and other states who now adamantly oppose any measures that would require vaccines or masks, saying they infringe on personal liberties. Their bans on mandates have been making their way through the courts for months.
A Texas hospital, Houston Methodist, was one of the first large health care facilities in the country to enforce a vaccine mandate in June, when more than 150 staff members were fired or resigned.
Facebook and Google, which maintain significant campuses in Texas, had said before Monday’s order that they would require proof of vaccination for employees to return to their offices.
American Airlines, based in Fort Worth, announced on Friday that more than 100,000 U.S.-based employees must get vaccinated.
J. David Goodman contributed reporting.
The Nets announced Tuesday that they were indefinitely barring Kyrie Irving from all games and practices until he was “eligible to be a full participant.”
Irving, the team’s starting point guard, had faced the prospect of being able to play only on the road with the Nets this season because of local coronavirus ordinances in New York that require most individuals to be at least partially vaccinated to enter facilities such as sports arenas. The Nets play their home games at Barclays Center in Brooklyn.
“Without a doubt, losing a player of Kyrie’s caliber hurts,” Sean Marks, the Nets’ general manager, said at a news conference. “I’m not going to deny that. But at the end of the day, our focus, our coaches’ focus and our organization’s focus needs to be on those players that are going to be involved here and participating fully.”
Irving has not spoken publicly about his vaccination status, asking instead for privacy, and the Nets had danced around the topic for weeks. In response to a question from The New York Times on Tuesday about whether Irving was vaccinated, Marks said: “If he was vaccinated, we wouldn’t be having this discussion. I think that’s probably pretty clear.”
Marks said Irving would not be paid for missed home games, and that the decision to keep Irving away from the team had been made by himself and by Joe Tsai, the Nets’ owner.
“Will there be pushback from Kyrie and his camp? I’m sure that this is not a decision that they like,” Marks said. “Kyrie loves to play basketball, wants to be out there, wants to be participating with his teammates. But again, this is a choice that Kyrie had and he was aware of that.”
Irving missed the Nets’ preseason home-opener against the Milwaukee Bucks after being listed as “ineligible” on the injury report. He also was not with the Nets in Philadelphia for their preseason game against the 76ers on Monday. Asked about his absence before the game, Steve Nash, the Nets’ coach, said: “We’re just trying to take our time to figure out what everything means.”
Irving’s potential absence from home games had created a predicament for the Nets, a team with championship aspirations that had to weigh whether having him around only half the time would be worth it. His teammates had expressed their support for him.
“It’ll work itself out,” James Harden said last week, adding: “I want him to be on the team, of course. He’s been a huge part of our success.”
On Tuesday, Marks said he would be willing to welcome Irving’s return to the team “under a different set of circumstances.”
Barclays Center and Madison Square Garden, where the Knicks play, require all employees and guests 12 and older to show proof of having received at least one vaccine dose, to comply with a city mandate, unless they have a religious or medical exemption. San Francisco has a similar requirement that applies to Chase Center, where the Golden State Warriors play. The mandates in both cities mean that the players from the Knicks, Nets and Golden State cannot play in their teams’ 41 home games without being vaccinated.
The ordinances in New York and San Francisco do not apply to players from visiting teams.
A federal judge ruled on Tuesday that New York State health officials must allow employers to grant religious exemptions to a Covid-19 vaccine mandate for health care workers while a lawsuit challenging the mandate makes its way through the courts.
The judge’s order at least temporarily thwarts Gov. Kathy M. Hochul’s effort to require immediate vaccination for health care workers even if they have religious objections. And it offers a reprieve for thousands of unvaccinated doctors, nurses and support workers who would have been prevented from working beginning Tuesday if the judge had ruled for the state.
A lawyer for a group of health care workers who are suing the state over the mandate hailed the ruling.
“With this decision, the court rightly recognized that yesterday’s ‘front line heroes’ in dealing with Covid cannot suddenly be treated as disease-carrying villains and kicked to the curb by the command of a state health bureaucracy,” said Christopher Ferrara of the Thomas More Society.
Ms. Hochul, in a statement, indicated the state would appeal.
“My responsibility as governor is to protect the people of this state, and requiring health care workers to get vaccinated accomplishes that,” Ms. Hochul said. “I stand behind this mandate, and I will fight this decision in court to keep New Yorkers safe.”
Former Gov. Andrew M. Cuomo issued the state’s first vaccine mandate for health workers in mid-August; it permitted religious exemptions.
But when Ms. Hochul’s administration issued its own mandate later that month — to take effect this fall — it rescinded the exemptions. That prompted 17 health care workers to sue the state in federal court, on the ground that the mandate conflicted with their religious beliefs.
Between the two governors’ orders, thousands of health care workers across the state had applied for or received a religious exemption.
In his 27-page ruling, Judge David N. Hurd of the Northern District in Utica wrote that New York appeared to overreach by barring all religious accommodations in the mandate. He issued a preliminary injunction preventing the Department of Health from acting against any employer who grants religious exemptions, and wrote that the 17 health care workers were likely to succeed in their case.
“The Department of Health is barred from interfering in any way with the granting of religious exemptions from Covid-19 vaccination going forward, or with the operation of exemptions already granted,” Judge Hurd wrote.
The judge had earlier issued a temporary restraining order barring the state from enforcing the mandate against people with religious objections starting in mid-September; technically, Tuesday’s order extended that ruling. The restraining order effectively allowed many health workers who applied for religious exemptions in New York to continue working even after the mandate went into effect.
In the federal case, titled Dr. A et al v. Hochul, the 17 health care workers argued that they could not consent to be inoculated with vaccines “that were tested, developed or produced with fetal cell lines derived from procured abortions.”
Pope Francis has said that Catholics may get the Covid-19 vaccines; most of the health care workers suing in the case are Catholic. But Judge Hurd did not question whether the health care workers were correct in their religious objections. Instead, he focused on their broader constitutional right to have their religious beliefs considered, and when possible, accommodated.
In his ruling on Tuesday, Judge Hurd looked at how the mandates differed from one governor to the next. “This intentional change in language is the kind of ‘religious gerrymander’ that triggers heightened scrutiny,” the judge wrote.
Fully vaccinated travelers from low-risk countries, including the United States and China, would be allowed to visit Thailand without undergoing quarantine starting Nov. 1, under a plan announced by the country’s prime minister, Prayuth Chan-ocha.
Health officials are expected to approve the plan, which calls for the lifting of restrictions for tourists from 10 countries. It would be the first step in a phased reopening strategy that would lead to the resumption of service at entertainment venues as early as Dec. 1, he said in an address Monday evening.
Before the pandemic, Thailand’s economy was highly dependent on tourism and attracted nearly 40 million tourists in 2019, with more than a quarter coming from China. Bangkok, the capital, often ranks in surveys as the world’s most visited city. Thailand was among the most successful countries in containing the virus last year. But it was slow in procuring vaccines and has seen a surge of cases this year.
The prime minister said that Thailand must learn to live with the virus, noting that other nations were already taking steps to reopen to tourists, and that Thailand must act quickly to lure millions of visitors for the New Year holidays.
Under Mr. Prayuth’s plan, fully vaccinated visitors from the 10 countries would be required to show proof of a negative PCR test before departure, and to take another test upon arrival. After testing negative, they would be free to travel around Thailand. Visitors from countries not on the list would still face quarantines and other restrictions.
A ban on restaurants serving alcohol — a rule widely flouted in Bangkok — would remain in place until at least Dec. 1, he said.
In July, Thailand began allowing vaccinated tourists who tested negative to visit the island of Phuket under a program called the Phuket Sandbox. After 14 days, they were allowed to travel freely in Thailand. That period has since been reduced to seven days. Thailand has increased its vaccine supply in recent weeks and launched an aggressive inoculation campaign, vaccinating as many as 1 million people a day.
“The time has come for us to ready ourselves to face the coronavirus and live with it as with other endemic infections and disease,” Mr. Prayuth said.
The German company CureVac announced on Tuesday that it was withdrawing its mRNA vaccine for Covid-19 from the approval process in Europe. The company pulled the plug after determining that it might take until June for regulators to make a ruling about the vaccine.
With other mRNA vaccines from Moderna and Pfizer-BioNTech already in wide distribution, the company decided it was time to give up on its initial efforts to address the Covid-19 emergency.
“The pandemic window is closing,” Franz-Werner Haas, CureVac’s chief executive, said in an interview.
The company will also terminate its advance agreement with the European Commission to sell it 405 million doses of the vaccine after approval.
But in the longer term, CureVac is not out of the Covid-19 vaccine business. The company is partnering with the pharmaceutical giant GSK to start a clinical trial of a new version of the vaccine that they hope will be more effective. The companies are also investigating how to combine seasonal booster shots to work against both Covid-19 and influenza.
Founded 20 years ago, CureVac pioneered early research on mRNA vaccines along with the German firm BioNTech and the U.S. company Moderna. At the start of the Covid-19 pandemic, all three companies developed new vaccines against the coronavirus.
While Moderna and BioNTech moved swiftly into clinical trials, CureVac was slower to find partners to support its vaccine’s development. Nevertheless, some experts saw promise in the CureVac shot, hoping that it could help address the global shortfall in Covid vaccines.
The European Medicines Agency gave CureVac special priority for its application, cutting the time needed for authorization. But in June, the company made a disappointing announcement: A clinical trial found that the vaccine’s efficacy was just 48 percent. By comparison, the vaccines from BioNTech and Moderna had efficacies around 95 percent.
Despite that disappointment, CureVac went ahead with its application for authorization in Europe, and submitted a final data package in September. In its updated application, CureVac asked that the vaccine be considered only for people 18 to 60 years old. In that group, the clinical trial had found a moderately higher vaccine efficacy, of 53 percent.
The European regulators’ response was less than encouraging. “We were not being lined up for emergency review,” said Dr. Klaus Edvardsen, the company’s chief development officer.
CureVac’s Covid-19 vaccine is now the seventh to be abandoned after entering clinical trials. Last month, Sanofi announced it was giving up on its mRNA vaccine.
But CureVac’s newer version may have more success. In August, the company shared the results of an experiment on monkeys, showing that the new vaccine generated 10 times as many antibodies against the coronavirus as the original one did. CureVac will begin testing it in people in the next couple of months.
Dr. Haas said the company’s strategy is now “to be fast with a second generation rather than to be very late with the first generation.”
An earlier version of this article misstated the efficacy of the CureVac vaccine. It was 48 percent, not 47. It also misstated the age range for which the company asked regulators to consider vaccine approval. It was ages 18 to 60, not under 65.
In their struggle to convince holdouts to get vaccinated against Covid, governments around the world are embracing vaccine mandates.
The push to get people vaccinated has largely shifted from offering incentives, like cash payouts or free drinks, to issuing mandates and restricting the access of the unvaccinated to many venues and activities.
Care to sip an espresso indoors at a cafe in Paris? You will need to provide proof of vaccination or a fresh negative coronavirus test, for which unvaccinated people will have to pay beginning on Oct. 15.
Want to work in settings like offices, factories, shops and restaurants in Italy? Starting later this month, you will need to have recently recovered from Covid-19, provide proof of having received at least one dose of a vaccine, or get a coronavirus test every two days. In areas of high coronavirus transmission in Greece, live music is returning indoors to restaurants and bars for a two-week trial, but the unvaccinated will not be admitted.
Italian and French officials announced their measures in July. Greece announced its shift last week. In early August, New York became the first U.S. city to require proof of vaccination for indoor dining, gyms and movie theaters.
Since then, San Francisco, Los Angeles and other cities have announced their own vaccine requirements to engage in public activities.
As the latest wave of infections has begun to wane around much of the U.S., President Biden’s administration has increasingly turned to mandates, drawing fire in the process from many Republican leaders who perceive them as government overreach. On Thursday, he urged private employers to impose mandates of their own as the Occupational Safety and Health Administration works out the details of a vaccine or testing requirement for companies with more than 100 employers.
Vaccine mandates have sparked resentment and refusal to comply from the unvaccinated.
France’s restrictions spurred large protests this summer, but those protests have mostly cooled, and as of Oct. 7, 67 percent of the population was fully vaccinated, more than double the level from early July, according to the Our World in Data project at the University of Oxford. An additional 8.3 percent were partly vaccinated as of Oct. 7.
Vaccine requirements remain politically toxic in some parts of the United States. Republican governors like Greg Abbott of Texas and Ron DeSantis of Florida have enacted rules that penalize businesses that require proof of vaccination and prohibit local governments from mandating such requirements.
On Monday, Mr. Abbott signed an executive order that broadened a previous ban on vaccine mandates by barring private companies from imposing them.
“The COVID-19 vaccine is safe, effective, and our best defense against the virus, but should remain voluntary and never forced,” the governor said in a statement.
The A.C.L.U., on the other hand, has defended vaccine mandates, saying they protect the civil liberties the organization defends.
“They protect the most vulnerable among us, including people with disabilities and fragile immune systems, children too young to be vaccinated and communities of color hit hard by the disease,” David Cole, the national legal director of the A.C.L.U., and Daniel Mach, director of its program on freedom of religion and belief, wrote in a New York Times editorial in September.
Some organizations that encourage vaccinations feel that mandates could be counterproductive, like the Wyoming Hospital Association. Eric Boley, the association’s president, said that vaccination was critical, especially for health workers, but that mandates could drive away staff that Wyoming’s hospitals urgently need.
By the holiday season, flying will have changed significantly for Americans returning to the United States from abroad. They will be asked to show proof that they are vaccinated, to commit to two coronavirus tests if they are not and to participate in a new contact tracing system.
For Americans traveling within the United States, however, none of this applies. As airlines prepare for what’s expected to be the biggest travel rush of the past two years, domestic travel — aside from a mask mandate and some restrictions on alcohol — will be largely the same as it was before the pandemic: packed cabins and no testing or proof of vaccination required.
Whether this is a symptom of denial or a sign of progress depends on whom you ask. Senator Dianne Feinstein, Democrat of California, recently telegraphed her position when she proposed a bill that would require passengers on domestic flights to be fully vaccinated, to have recently tested negative or to have a certificate of recovery from the virus.
“We know that air travel during the 2020 holiday season contributed to last winter’s devastating COVID-19 surge,” Ms. Feinstein said in a statement. “We simply cannot allow that to happen again.”
Dr. Anthony S. Fauci, President Biden’s top medical adviser, has said he personally supports requiring proof of vaccination for domestic air travel, a policy that Canada will begin putting in place on Oct. 30. But the White House has said it is focused on other strategies for encouraging broad vaccination.
On Jan. 9, 2020, about a week after the world first learned of a mysterious cluster of pneumonia cases in central China, authorities announced that scientists had found the culprit: a novel coronavirus.
It was a sobering announcement, and an unnervingly familiar one. Nearly two decades earlier, a different coronavirus had sped around the world, causing a lethal new disease — severe acute respiratory syndrome, or SARS. It killed 774 people before health officials contained it.
But even as scientists worried that history may be repeating itself, there was one glimmer of hope. Although all viruses evolve, coronaviruses are known to be relatively stable, changing more slowly than the common flu.
What many scientists had not counted on was unchecked global spread. Over the following weeks, the new virus, SARS-CoV-2, skipped from Wuhan, China, to a cruise ship in Japan, to a small town in northern Italy and to a biotechnology conference in Boston. Country by country, global coronavirus trackers turned red.
To date, more than 237 million people have been infected with the virus, and 4.8 million have died — 700,000 in the United States alone.
With every infection come new opportunities for the virus to mutate. Now, nearly two years into the pandemic, we are working our way through an alphabet of new viral variants: fast-spreading Alpha, immune-evading Beta, and on through Gamma, Delta, Lambda and, most recently, Mu.
Even for a virus, evolution is a long game, and our relationship with Covid-19 is still in its infancy. We are extremely unlikely to eradicate the virus, scientists say, and what the next few years — and decades — hold is difficult to predict.
But the legacy of past epidemics, as well as some basic biological principles, provides clues to where we could be headed.
It’s difficult to parse how immunity from infection from the coronavirus and from vaccination compare. Dozens of studies have delved into the debate, and have drawn contradictory conclusions.
Some consistent patterns have emerged. Two doses of an mRNA vaccine produce more antibodies, and more reliably, than an infection does. But the antibodies from a previous infection are more diverse, capable of fending off a wider range of variants, than those produced by vaccines.
Studies touting the durability and strength of natural immunity are hobbled by one crucial flaw. They are, by definition, assessing the responses only of people who survived Covid-19.
Only 85 percent to 90 percent of people who test positive for the virus and recover have detectable antibodies to begin with. The strength and durability of the response is variable.
For example, while the immunity gained from vaccines and infection is comparable among younger people, two doses of the mRNA vaccines protected adults older than 65 better than a prior infection did.
Research published in May showed a stepwise increase in the level of antibodies with rising severity of infection. About 43 percent of recovered people had no detectable neutralizing antibodies — the kind needed to prevent reinfection — according to one study. The antibodies drop to undetectable levels after about two months in about 30 percent of people who recover.
Several studies have now shown that reinfections, at least with the earlier versions of the virus, are rare.
At the Cleveland Clinic, none of 1,359 health care workers who remained unvaccinated after having Covid-19 tested positive for the virus over many months.
But the clinic tested only people who were visibly ill, and may have missed reinfections that did not produce symptoms. The participants were 39 years old on average, so the results may not apply to older adults, who would be more likely to become infected again.
Covid-19’s waves of destruction have inflicted their own kind of despair on humanity in the 21st century, leaving many to wonder when the pandemic will end.
“We tend to think of pandemics and epidemics as episodic,” said Allan Brandt, a historian of science and medicine at Harvard University. “But we are living in the Covid-19 era, not the Covid-19 crisis. There will be a lot of changes that are substantial and persistent. We won’t look back and say, ‘That was a terrible time, but it’s over.’ We will be dealing with many of the ramifications of Covid-19 for decades, for decades.”
Especially in the months before the Delta variant became dominant, the pandemic seemed like it should be nearly over.
“When the vaccines first came out, and we started getting shots in our own arms, so many of us felt physically and emotionally transformed,” said Dr. Jeremy Greene, a historian of medicine at Johns Hopkins University School of Medicine. “We had a willful desire to translate that as, ‘The pandemic has ended for me.’”
He added, “It was a willful delusion.”
That is a lesson from history that is often forgotten, Frank Snowden, a historian of medicine at Yale University, said: how difficult it is to declare that a pandemic has ended.
It may not be over even when physical disease, measured in illness and mortality, has greatly subsided. It may continue as the economy recovers and life returns to a semblance of normality. The lingering psychological shock of having lived in prolonged fear of severe illness, isolation and painful death takes long to fade.
Severely or moderately immunocompromised people who have been vaccinated should be offered an additional dose of the seven coronavirus vaccines the World Health Organization has authorized, an advisory committee recommended on Monday.
People whose immune systems are diminished should get another shot if they initially received vaccines made by Pfizer-BioNTech, Moderna, AstraZeneca, the Serum Institute of India, Johnson & Johnson, Sinopharm and Sinovac, members of the Strategic Advisory Group of Experts on Immunization told reporters on a call on Monday.
Dr. Alejandro Cravioto, the committee’s chair, said that people with compromised immune systems “need a third dose as an additional priming process so that they’re fully protected.”
The officials also recommended a third vaccine dose for people 60 and over who were inoculated with China’s Sinopharm and Sinovac vaccines, ideally of the same brand as their first course of treatment.
W.H.O. officials have previously said that they supported additional vaccine doses for immunocompromised people who were not sufficiently protected from a standard vaccination regimen, and some countries, including the United States, already administer them.
The committee was careful to distinguish its own recommendation for additional doses for immunocompromised people from booster shot regimens like those authorized in the United States, Israel and some European countries.
Those booster programs, largely intended to boost immunity in healthy individuals over certain ages, have drawn criticism from the W.H.O., which has called for a moratorium on boosters until the end of the year so that more of the world’s limited supply of vaccines can go to countries where few people have been vaccinated.
Dr. Katherine O’Brien, director of the W.H.O.’s department of immunization, vaccines and biologicals, called the panel’s recommendation “a distinct thing from giving additional doses, booster doses, to people who have had an adequate primary response to vaccination.”
Those boosters, she said, are “like putting two life jackets on somebody and leaving other people without any life jacket. So in this sense we’re talking about getting the first life jacket on to people who have immunocompromising conditions.”
She added that the W.H.O. had not yet determined that fully vaccinated, otherwise healthy people needed the added protection from boosters, but the committee planned to review booster issues during a session on Nov. 11.
The call with reporters on Monday was intended to summarize a series of meetings held last week, during which officials discussed global vaccine issues, like a newly approved vaccine for malaria.
New Jersey’s governor’s race, which is one of just two governor’s races in the country before next year’s midterm elections, is seen by some as an early barometer of voter sentiment.
Gov. Philip D. Murphy, a Democrat, has tried to lash Jack Ciattarelli, a Republican challenging his bid for re-election, to President Donald J. Trump, who lost to President Biden in New Jersey by 16 points.
But New Jersey’s election also offers one of the first statewide tests of how voters feel about strict coronavirus-related mandates as pandemic fatigue mounts.
Voters surveyed in polls continued to give Mr. Murphy some of his highest marks for the way he has responded to the pandemic, and he has said he believed it was the most defining issue separating him and Mr. Ciattarelli.
Last week, Mr. Murphy refused to rule out a Covid-19 vaccine mandate for students, a step taken only by California, where, as early as next fall, vaccination will be required to attend school.
Still, along the Jersey Shore in Ocean County, where Mr. Trump won by nearly 30 points, it remains easy to find anti-mask yard signs that read “Free the Smiles.” And across the state some local board of education meetings have grown tense with parents opposed to mask wearing in schools clashing with officials who are required to enforce the state mandate.
Registered Democrats in New Jersey outnumber Republicans by nearly 1.1 million voters, giving Mr. Murphy a built-in advantage that several polls have shown Mr. Ciattarelli is struggling to overcome.
A report released Friday by the Covid States Project, a research and tracking effort by several universities, found that governors of states with prohibitions on vaccine mandates, including Arkansas, Arizona and Idaho, got the lowest approval ratings.
Many law enforcement officers in the United States resist coronavirus vaccination even though Covid-19 has killed more law enforcement officers than any other work-related cause since the start of the pandemic.
More than 460 American law enforcement officers have died from Covid-19 infections tied to their work since the pandemic began, according to the Officer Down Memorial Page, making the coronavirus by far the most common cause of duty-related deaths in 2020 and 2021. More than four times as many officers have died from Covid-19 as from gunfire during the pandemic. There is no comprehensive accounting of how many American police officers have been sickened by the virus, but departments across the country have reported large outbreaks in the ranks.
While the virus has ravaged policing, persuading officers to take a vaccine has often been a struggle, even though the shots have proven to be largely effective in preventing severe disease and death.
Health departments generally do not publish vaccination data by occupation, but some cities have released figures showing that police department employees have been vaccinated at lower rates than most other government workers, and at lower rates than the general public. In Los Angeles, where vaccines are required for city workers, more than 2,600 employees of the police department said they intended to seek a religious exemption, though almost all major religious denominations support vaccines.
Some elected officials say police officers have a higher responsibility to get vaccinated because they are regularly interacting with members of the public and could unknowingly spread the virus. The debate echoes concerns from earlier in the pandemic, when police officers in some cities resisted wearing masks in public.
Yet as more departments in recent weeks have considered requiring members to be vaccinated, officers and their unions have loudly pushed back, in some cases threatening resignations or flooding systems with requests for exemptions.