A new study by the Centers for Disease Control and Prevention suggests that vaccination provides stronger and more reliable protection against the coronavirus than a past infection does, the agency said on Friday.Unvaccinated people who had previously recovered from a coronavirus infection were five times as likely to get Covid as people who had received both shots of the Pfizer-BioNTech or Moderna vaccines, the C.D.C. said.The study’s authors cautioned, however, that certain gaps in patient data and biases in their study participants could have influenced the results.“We now have additional evidence that reaffirms the importance of Covid-19 vaccines, even if you have had prior infection,” said Dr. Rochelle P. Walensky, the C.D.C. director, in a statement accompanying the release of the report.The question of whether people who have had Covid really need a shot has gained traction among some Americans as vaccine mandates take hold across the country. Scientists have urged Covid survivors not to skip the vaccine, noting that the strength and durability of so-called natural immunity depends heavily on people’s age and health, and the severity of an initial infection.The C.D.C. study used a roundabout experimental design. The researchers examined roughly 7,000 people hospitalized this year with Covid-like illness across nine states. They then looked at how many of those hospitalized patients were indeed infected with the coronavirus. The odds of testing positive for the virus were considerably higher among unvaccinated, previously infected patients than they were among vaccinated people.The study comes with several caveats, however. The researchers cautioned that the findings may not translate to non-hospitalized people with different levels of access to medical care, and that some patients in the vaccinated group may unknowingly have also had previous infections.The researchers also noted that separate research in Israel had failed to show that vaccinated people were better protected than those who had only been infected. In general, scientists said, studies on the topic had drawn contradictory conclusions.Still, some patterns have emerged. Two doses of an mRNA vaccine produce more antibodies, and more reliably so, than a coronavirus infection does. But the antibodies from prior infection are more diverse, potentially helping people fend off variants.Whatever the effect, doctors have warned that acquiring natural immunity is perilous and uncertain. Not everyone survives Covid in the first place, and those that do may not be able to count on a vigorous immune response.

The pandemic dealt a serious setback to global efforts to immunize children against diseases like measles and polio, the Centers for Disease Control and Prevention reported on Thursday, reducing worldwide coverage for some vaccines to levels not seen since more than a decade ago.The proportion of eligible children who received a polio vaccine fell to 83 percent in 2020 from 86 percent the year before, as did coverage with the third dose of the diphtheria-tetanus-pertussis vaccine, known as DTP3. Coverage with the measles vaccine also dipped slightly, to 84 percent last year from 86 percent in 2019.Those setbacks, while seemingly small, meant that millions more children missed out on routine immunizations during the pandemic, putting them and their communities at risk.Globally, nearly 23 million children targeted for the DTP3 shot were not vaccinated in 2020, compared with 19 million in 2019, the C.D.C. said. The vast majority of those had not received a single dose of diphtheria-tetanus-pertussis vaccine. Not since 2009 had coverage with that vaccine been so low.The C.D.C. scientists involved in the report called for action to be taken to address the immunity gaps of preventable diseases in countries already saddled with Covid outbreaks. Scientists from the World Health Organization and UNICEF also were co-authors on the study.The decline in vaccinations follows a decade of stagnant immunization levels. In 2019, measles deaths swelled to their highest levels in 23 years, a consequence of what public health experts described as insufficient vaccination coverage. Scientists said that the pandemic had hampered the tracking of measles outbreaks.The pandemic also disrupted immunization programs, the C.D.C. report said, interrupting the supply of basic vaccines and making it more difficult to administer them.Immunization levels for diphtheria-tetanus-pertussis and measles were lowest in much of Africa, the report said. The W.H.O. also said on Thursday that only five of Africa’s 54 nations were expected to reach a year-end goal of vaccinating 40 percent of their people against Covid. UNICEF, a United Nations agency working to distribute coronavirus vaccines, warned of a shortfall next year in syringes for both Covid and routine vaccinations.

A large clinical trial has found that a common and inexpensive antidepressant lowered the odds that high-risk Covid-19 patients would be hospitalized. The results, published on Wednesday, could open the door to new guidelines for the drug’s use both in the United States and globally.The drug, fluvoxamine, has been safely prescribed for nearly 30 years as a treatment for obsessive-compulsive disorder. But when the coronavirus started spreading, researchers were drawn to the medication because of its ability to reduce inflammation, potentially allowing it to quell the body’s overwhelming response to a coronavirus infection.Several smaller studies of fluvoxamine earlier in the pandemic showed promising results, but none was as large or persuasive as the one published on Wednesday by a group of researchers in Canada, the United States and Brazil, outside scientists said. Among nearly 1,500 Covid patients in Brazil given either fluvoxamine or a placebo, the drug reduced the need for hospitalization or prolonged medical observation by one-third, the study found. It was published in The Lancet Global Health.Some patients struggled to tolerate the drug and stopped taking it, the study said, raising a question among outside scientists about whether they had yet identified the ideal dose. But among those who had largely followed doctors’ orders, the benefits were even more striking. In those patients, the drug reduced the need for hospitalization by two-thirds and slashed the risk of dying: One Covid patient given fluvoxamine died, compared with 12 given a placebo.“That’s really good,” said Dr. David Boulware, an infectious disease scientist at the University of Minnesota who worked on a smaller, real-world study of the drug in Covid patients in California. Plus, he added, “it’s not a shiny new, expensive drug. The nice thing about this is it has a known safety profile.”Beyond proper dosing, the study left other questions unresolved, scientists said. Penny Ward, a visiting professor in pharmaceutical medicine at King’s College London, noted that part of the drug’s benefit appeared to come from reducing the need for extended medical observation, which the study tracked alongside hospital admissions. And most patients in the study were unvaccinated, Professor Ward said, so it’s unclear how well the drug would work in the vaccinated.The new study, coming nearly a year after smaller trials of the drug, was a reminder of the difficulty that many researchers have had running large tests of Covid treatments. The Biden administration has made more funding available for such trials, scientists said, but enrolling enough patients has only gotten more difficult: Most high-risk Americans are vaccinated, and vaccine-averse people may be less likely to participate in trials.Because fluvoxamine is already approved for treating O.C.D., doctors can already prescribe it “off label” for Covid. But Dr. Boulware said that prescriptions of the drug had increased only slightly during the pandemic, unlike other repurposed drugs with far less scientific support, like hydroxychloroquine and ivermectin.“It hasn’t really gotten any cult following,” he said.Federal treatment guidelines say that larger trials are necessary to evaluate the use of fluvoxamine for Covid, and scientists said they expected those recommendations to change on the basis of the new study.The new findings are also expected to boost the popularity of the drug in less wealthy countries: A 10-day course of the drug costs about $4.

Scientists from the Centers for Disease Control and Prevention on Friday took aim at the question of whether the Delta variant of the coronavirus causes more severe disease, finding no significant differences in the course of hospitalized patients’ illnesses during the Delta wave compared to earlier in the pandemic.But larger and more detailed studies from a number of other countries have found that people with Delta infections were considerably more likely to be hospitalized in the first place — a trend that the C.D.C. study was unable to address because of limitations in its data. The C.D.C. study also said that the proportion of older hospitalized patients needing intensive care or dying had shown some signs of increasing during the Delta wave.Delta’s higher level of infectiousness has made it a far greater challenge than earlier versions of the virus, but the question of whether it also causes more serious disease has loomed as it swept around the world. The Alpha variant, an earlier version first detected in Britain, appeared to be linked to a higher risk of death, though scientists have also tried to understand whether factors besides the variant were playing a role.Studies in England, Scotland, Canada and Singapore suggested that the Delta variant was associated with more severe illness, a finding that scientists have said raises the risk that outbreaks of the variant in unvaccinated areas may put a bigger burden on health systems. Unlike the C.D.C. study, those studies drew on genomic sequencing, allowing researchers to distinguish infections with the Delta variant and to track patients from before they enter a hospital.Without access to sequencing data, the C.D.C. researchers could not determine which variants the patients may have been infected with. It also examined patients already admitted to hospitals, making it impossible to determine whether they were at higher risk of needing hospital care in the first place.The study, released on Friday, examined roughly 7,600 Covid hospitalizations, comparing July and August — when Delta dominated — to earlier months this year, and found no significant change in hospitalized patients’ outcomes.The study said that the proportion of hospitalized patients aged 50 and older who died or were admitted to intensive care “generally trended upward in the Delta period,” though the differences were not statistically significant and further work was needed. At the hospitals included in the study, roughly 70 percent of Covid patients were unvaccinated.The researchers said the findings matched those of other C.D.C. studies using similar methods that showed no significant differences in the outcomes of younger people hospitalized before and during the Delta surge.Outside scientists questioned the reliability of the study. Dr. David Fisman, an epidemiologist at the University of Toronto, ran a larger study that found that people infected with the Delta variant had roughly twice the risk of hospitalization as people infected with variants that had not been labeled a concern. He said that such analyses needed to control for the range of factors that affect the course of Covid patients’ illnesses, and that the availability of vaccines, testing and treatments had all been changing during the pandemic.“As this is the U.S. C.D.C., I’m really surprised at the small sample sizes for individuals with more detailed clinical information, as well as the use of such rudimentary statistical methods to deal with these data,” he said.Dr. Fisman’s study, drawing on 200,000 cases and published this month, also showed significantly increased risks of intensive care admission and death among those infected with the Delta variant, after accounting for their age, sex, vaccination status and other factors. Roughly 70 percent of people with Delta infections in the study were unvaccinated, and 28 percent were partially vaccinated. Fully vaccinated people are heavily protected from Covid.Similarly, a study in Scotland from June based on 20,000 Covid cases showed that Delta infections were associated with an 85 percent higher risk of hospitalization, though it allowed for a wide degree of uncertainty about the precise figure.And data from England, drawn from 43,000 cases and published in August, found that people infected with the Delta variant were just over twice as likely to be hospitalized as people with the Alpha variant, though the researchers in that study, too, were unsure of the precise figure.Roughly three-quarters of the patients in that study were unvaccinated, and most of the rest were only partially vaccinated.

The Pfizer-BioNTech vaccine was 93 percent effective against hospitalization with Covid-19 among 12- to 18-year-olds, the Centers for Disease Control and Prevention reported on Tuesday, the strongest evidence to date of the vaccine’s ability to keep young people out of the hospital.With federal regulators now considering authorizing the vaccine for children ages 5 to 11, the study offered additional signs that extending vaccines to more young people could not only reduce the spread of the virus in the United States, but also protect those children from the rare cases in which they become severely ill.“This evaluation demonstrated that two doses of Pfizer-BioNTech vaccine are highly effective at preventing Covid-19 hospitalization among persons aged 12–18 years,” the agency’s scientists wrote, “and reinforces the importance of vaccination to protect U.S. youths against severe Covid-19.”The agency studied young people who were hospitalized at 19 pediatric hospitals across 16 states from June through September, as the Delta variant spread across the country and exacted a devastating toll in less-vaccinated states in the South and West. It compared the odds of vaccination among children hospitalized with Covid and children hospitalized with other illnesses.Among the 179 patients in the study who had Covid, three percent were vaccinated and 97 percent were unvaccinated. Twenty-nine of the young Covid patients needed life support, and two died; all of those patients were unvaccinated, the agency said. Vaccinated children with Covid also tended to have shorter hospital stays than unvaccinated children.Nearly three-quarters of the Covid patients in the study had at least one underlying health condition, including obesity, diabetes, asthma or respiratory disorders, putting them at higher risk of severe illness.As of Monday, the C.D.C. said, 46 percent of children ages 12 to 15 were fully vaccinated nationwide, as were 54 percent of 16- and 17-year-olds. The Pfizer-BioNTech vaccine is authorized for emergency use in children ages 12 to 15, and fully approved in people ages 16 and over. Booster shots have not been authorized for anyone in the United States under 18 years old.Pediatric hospitalizations rose as the Delta variant spread across the United States, reaching their highest level during the pandemic in September, the C.D.C. said.A clinical trial of the Pfizer-BioNTech vaccine had earlier shown that the shots were highly effective at preventing Covid cases in children, but had not examined effectiveness against hospitalization in that group.

“This new group can do all the fancy footwork it wants, but China’s not going to cooperate,” one expert said.The position is unpaid. The world’s scientists and internet sleuths will scrutinize every move. Completing the first assignment with the available tools, and to everyone’s satisfaction, will be nearly impossible.Despite those considerable obstacles, more than 700 people have applied for spots on a new committee charged with breathing life into the World Health Organization’s stalled inquiry into the origins of the coronavirus pandemic.The committee, expected to be announced this week, represents an attempt by the embattled global health body to reset its approach to determining how the pandemic began. Nine months after sending a team of international experts to China, only for its findings to become entangled in geopolitics and trailed by concerns over Beijing’s influence, the W.H.O. is trying to inoculate its latest efforts from the slightest hints of undue deference toward China.Its new advisory team will include specialists in fields like laboratory safety and biosecurity, a step that analysts say may help placate Western governments pressing for consideration of whether the virus emerged from a lab. And, crucially, the committee will have a mandate to weigh in on the emergence of any new pathogens beyond this novel coronavirus, giving it a permanence that could help insulate it from political squabbling and strengthen the W.H.O.’s hand for future outbreaks.Maria Van Kerkhove, the W.H.O.’s Covid-19 technical lead, said the group — comprising some two dozen virologists, geneticists, animal experts and safety and security specialists — would help the organization return to its roots amid the rancor and partisanship of the coronavirus origins debate.“Especially in light of the politicization of this particular aspect,” she said in an interview, “we want to take this back to the science, take this back to our mandate as an organization to bring together the world’s best minds to outline what needs to be done.”What most needs doing in the hunt for Covid’s origins, many scientists believe, is something that the new advisory group will be powerless to achieve: persuading China to release evidence about the first infections and to let researchers inspect virology labs, bat caves and wildlife farms within its borders.China has reacted angrily to the idea that the virus may have emerged from a lab, pushing instead for investigations into early cases in other countries, like Italy, or into American research facilities.“This new group can do all the fancy footwork it wants, but China’s not going to cooperate,” said David Fidler, a senior fellow for global health at the Council on Foreign Relations, a research institute. “For them, all of this continues to look like an attack on China’s response to the pandemic, and there it’s a zero-sum game.”Maria Van Kerkhove, the W.H.O.’s Covid-19 technical lead. “We want to take this back to the science,” she said of the new team.Martial Trezzini/Keystone, via Associated PressSince the beginning of the pandemic, the W.H.O. has been caught in the middle of a tug of war between China and the United States — first over China’s response in the early days of the pandemic, and more recently over the question of how the virus emerged.Even as China has resisted deeper studies of the virus’s origins, the Biden administration has pressed the W.H.O. for a renewed investigation. The State Department pointedly questioned the results of a joint study by the W.H.O.-chosen scientists and Chinese researchers from March that said a leak of the coronavirus from a lab, while possible, was “extremely unlikely.”That W.H.O. team, too, struggled to coax the data it needed from Chinese scientists. Members of the team, which has been disbanded, warned in August that time was running out to recover crucial evidence about the beginning of the pandemic. But it is unclear whether China has taken up the team’s recommendations for future studies, including analyzing blood banks for evidence of early coronavirus infections, testing workers on wildlife farms and assessing wild bats and farmed animals for signs of exposure.Some scientists have said that studies of Chinese animal markets, and of bats harboring close relatives of the virus behind Covid-19, have strengthened their belief that the coronavirus spilled naturally from animals into humans.The W.H.O. has said that Chinese researchers were conducting new studies but that it had not been kept abreast of any findings. “I don’t have any detail on what was done, or is being done,” Dr. Van Kerkhove said of the Chinese research.President Xi Jinping said last month that China would support “science-based origins tracing,” but would oppose “political maneuvering in whatever form.”The Wuhan Institute of Virology during the W.H.O.’s investigation team’s visit last winter.Thomas Peter/ReutersThe new committee, known as the Scientific Advisory Group for the Origins of Novel Pathogens, will differ in several respects from the team that the W.H.O. sent to China. Because that team visited Wuhan, China had considerable influence over its membership. That is not the case for the new committee, a permanent panel that Dr. Van Kerkhove said would begin with frequent, closed-door meetings on the coronavirus.In soliciting applications, the W.H.O. asked potential committee members for a statement about any conflicts of interest, in addition to a cover letter and résumé. That appeared to be an attempt to head off critics who complained that a member of the previous team, Peter Daszak, an animal disease specialist, was too closely tied to a Wuhan virology institute at the center of lab leak theories to offer a dispassionate assessment. Dr. Daszak has said that his expertise on China and coronaviruses made him well-suited to participate in the earlier trip.“Conflicts of interest of members of the last group put a huge cloud over the head of the World Health Organization,” said Lawrence Gostin, who directs the O’Neill Institute for National and Global Health Law at Georgetown University. Of the new advisory group, he added: “It’s a committee with a proper charge, and a proper global mandate — none of that happened before.”For the W.H.O., Professor Gostin said, the new committee serves several purposes. In choosing a larger group reflecting a wider range of expertise and geographic regions, the organization can try to amass widespread international support for its work and underscore China’s intransigence, he said.Crucially, forming the new group could also help shore up the W.H.O.’s standing with its key Western backers, none more important than the United States. Despite the agency’s attempt to act deferentially toward China during the pandemic, Professor Gostin said, China had repeatedly stonewalled the organization and concealed crucial information.Now, he said, the organization needed to pay heed to the desires of Europe and the United States — not least because Tedros Adhanom Ghebreyesus, the W.H.O. director-general, is counting on their support as he seeks re-election in May. Tedros Adhanom Ghebreyesus, the W.H.O. director-general, will be seeking re-election next May.Christopher Black/World Health Organization, via Agence France-Presse — Getty Images“It was one thing to lose America under Donald Trump, where there was a great deal of sympathy for the W.H.O.,” Professor Gostin said. “It’s quite another thing to do it with President Biden, who is an internationalist and who does support the W.H.O.”Despite the eventual avalanche of applications, recruiting for the new committee was no simple task. In some cases, scientists rebuffed the W.H.O.’s pleas to apply.“We did have some people say to us, ‘No, we really don’t want to get engaged, because it’s just too politicized,’” Dr. Van Kerkhove said.The composition of the committee remains under tight wraps. Members of the W.H.O. team that traveled to Wuhan were allowed to apply. Dr. Van Kerkhove declined to say whether any Chinese scientists would be selected. She said that some countries had nominated participants, but that the internal W.H.O. selection group had not taken countries’ backing into account.She said the new committee would meet for the first time roughly two weeks after it is named, following a public comment period that is standard for the global health body’s advisory groups.“It will be a relief to have the first couple of meetings,” Dr. Van Kerkhove said. “But, you know, any time I feel like I’ve reached some kind of finish line, it’s really just a start.”

The arrival of vaccines and declining Covid-19 cases in the first half of 2021 coincided with an easing of symptoms of anxiety and depression across the United States, according to survey data released on Tuesday by the Centers for Disease Control and Prevention.But symptoms remained much more common in June 2021, the end of the survey period, than before the pandemic, and could be on the rise again because of the summer surge in cases of the Delta variant, C.D.C. scientists said.The agency relied on a biweekly online survey conducted from August 2020 to June 2021. Researchers analyzed 1.5 million responses over that period about the severity of symptoms of anxiety or depression.From August to December 2020, symptoms of anxiety rose by 13 percent and symptoms of depression by 15 percent, the surveys found. But from December to June 2021, that trend reversed: Symptoms of anxiety decreased by 27 percent and of depression by 25 percent.The C.D.C. said that there was a strong correlation between the average number of daily Covid-19 cases and the severity of respondents’ anxiety and depression.Noting that some parts of the population had been harder hit by the virus than others, the agency said those same groups may be at higher risk for psychological ill effects from Covid-19 and that good access to mental health services was critical. Other research has indicated that people with low incomes were at higher risk of depression during the pandemic.The national trends were mirrored in most states, with anxiety and depression peaking in December 2020 or January 2021, when U.S. cases, hospitalizations and deaths all peaked. States that experienced steeper increases in symptoms last year also showed larger reductions in the first half of 2021.Mississippi was among the states with the largest increases in anxiety and depression scores by percentage in the second half of 2020. New York, on the other hand, experienced both the smallest rise in anxiety scores in late 2020 and the smallest drop in the first half of this year.

Americans with a disability were more likely to want coronavirus vaccines but were having a harder time getting them than other people, according to data released on Thursday by the Centers for Disease Control and Prevention, a stark signal of what the agency’s scientists said was a need for health officials to remove barriers to access.In a survey of nearly 57,000 people from May to June, unvaccinated people with a disability such as serious difficulty seeing, hearing or walking were nearly twice as likely as their unvaccinated counterparts without a disability to say that they would definitely get vaccinated. (The survey only included people outside of nursing homes and other institutions.)And yet, people with a disability were less likely to be vaccinated: Among 50- to 64-year-olds, 63 percent of people with a disability had received coronavirus shots, compared with 72 percent of other people. Among people older than 75, the gap was smaller but still evident: Eighty-eight percent of people with a disability were vaccinated, compared with 90 percent of people without one.“Covid-19 vaccination coverage was lower among U.S. adults with a disability than among those without a disability, even though adults with a disability reported less hesitancy to getting vaccinated,” the study’s authors wrote.The study noted that state-run vaccine registration websites were not all compliant with basic accessibility recommendations. It suggested that online scheduling systems offer call lines for people who needed help booking vaccinations.It also said that not all vaccination sites had American Sign Language interpreters or workers trained in helping people with developmental disabilities, and that getting to those sites in the first place was often difficult for people with a disability.“These efforts would be relevant to the reduction of health disparities related to disability beyond the Covid-19 pandemic,” the study said.

Americans who received a third dose of a coronavirus vaccine in recent weeks reported side effects at roughly the same rates as they had after their second shots, the Centers for Disease Control and Prevention said on Tuesday, a reassuring sign about the safety of additional doses.At the time of the C.D.C. study, which stretched from mid-August to mid-September, additional vaccine doses were only authorized for people with compromised immune systems who had gotten two doses of the Pfizer-BioNTech or Moderna vaccine. Last week, though, federal regulators authorized Pfizer booster shots for broad swaths of the general population, making the safety of the additional doses an issue of intense interest for health officials, doctors and ordinary Americans.The C.D.C. analyzed how commonly people reported side effects after a third dose compared with a second among 12,600 recipients who had filled out surveys as part of a voluntary safety monitoring system.Reactions at the injection site, like pain or swelling, were reported by 79.4 percent of recipients after a third vaccine dose, compared with 77.6 percent after a second dose. Slightly smaller numbers of people experienced systemic reactions, like a fever or headache: 74.1 percent of people reported those side effects after dose three, compared with 76.5 percent after dose two.“Most reported local and systemic reactions were mild to moderate, transient, and most frequently reported the day after vaccination,” the study’s authors said.The study focused on people who had received a third dose of the same vaccine that they had originally received, either from Pfizer-BioNTech or Moderna. The C.D.C. said that too few people had reported receiving an additional dose of the Johnson & Johnson vaccine, or an additional dose from a different vaccine maker than they had originally received, to study those side effects.The results reinforced findings from a small clinical trial of third shots of the Pfizer vaccine that the company’s scientists outlined to federal medical advisers last week. That trial, too, found that adverse reactions after a third dose were similar to those after a second.While the C.D.C. study covered only a period when people with immune problems were eligible for additional doses, the data likely also included people without such conditions who had nevertheless received a third shot, the study’s authors wrote. In all, the study said, about 2.2 million people had received additional doses by Sept. 19, the end of the C.D.C. study period.

When President Biden announced in June that the United States would buy 500 million Pfizer-BioNTech coronavirus vaccine doses for poorer nations, there was a gaping hole in his plan: To fund it, the administration quietly diverted hundreds of millions of dollars that had already been promised to countries for helping to get shots into people’s arms.Mr. Biden did not make the same mistake a second time.His announcement on Wednesday that the United States was donating an additional 500 million Pfizer doses came paired with a promise of an additional $750 million for vaccine distribution, roughly half of it through a nonprofit involved in global vaccinations. That reflected a growing awareness on the part of global leaders that turning vaccines into actual vaccinations represents one of the most significant challenges of this phase of the pandemic.Even so, the Biden administration’s schedule for shipping the newly announced Pfizer doses frustrated activists: Of the 1.1 billion doses that the United States has committed to donations, only 300 million are expected to be shipped this year. The longer the virus circulates around the world, the more dangerous it can become, even for vaccinated people in wealthy countries, scientists have warned.“Purchasing doses for donation sometime next year is helpful, but it does not meaningfully expand the global supply, and it is not justice,” said Peter Maybarduk, the director of the Access to Medicines program at Public Citizen, an advocacy organization.Some experts pleaded for more aggressive action by Mr. Biden to pressure American vaccine makers to share their formulas with nations that desperately need more shots.“Where is the monthly calendar of what each wealthy country is going to deliver?” said Kate Elder, senior vaccines policy adviser for Doctors Without Borders’ Access Campaign. She added, “Where are the announcements about meeting the calls of regions and middle-income countries that are begging to be self-sufficient?”It was not immediately clear how the administration was planning to allocate the new money for vaccine distributions. Some countries have been struggling to train and pay vaccinators and to transport doses. Pfizer doses present especially steep challenges: They must be stored at ultralow temperatures, requiring the installation of freezers and, in many cases, backup generators.Early this year, supply shortages represented the most pressing problem for global vaccinations. Rich nations had raced to secure doses while slow-walking pledges of money and supplies to Covax, the United Nations-backed program to immunize the world.But as those manufacturing difficulties have eased, different problems emerged. One was blatant inequality: More than 5.9 billion shots have been given globally, but overwhelmingly in wealthier nations. Another was that poorer countries had been left without the money needed to move shots from airport tarmacs into people’s arms.Although the Biden administration’s pledges have outpaced those of most Western nations, analysts said other wealthy countries were setting an extraordinarily low bar..css-1xzcza9{list-style-type:disc;padding-inline-start:1em;}.css-3btd0c{font-family:nyt-franklin,helvetica,arial,sans-serif;font-size:1rem;line-height:1.375rem;color:#333;margin-bottom:0.78125rem;}@media (min-width:740px){.css-3btd0c{font-size:1.0625rem;line-height:1.5rem;margin-bottom:0.9375rem;}}.css-3btd0c strong{font-weight:600;}.css-3btd0c em{font-style:italic;}.css-w739ur{margin:0 auto 5px;font-family:nyt-franklin,helvetica,arial,sans-serif;font-weight:700;font-size:1.125rem;line-height:1.3125rem;color:#121212;}#NYT_BELOW_MAIN_CONTENT_REGION .css-w739ur{font-family:nyt-cheltenham,georgia,’times new roman’,times,serif;font-weight:700;font-size:1.375rem;line-height:1.625rem;}@media (min-width:740px){#NYT_BELOW_MAIN_CONTENT_REGION .css-w739ur{font-size:1.6875rem;line-height:1.875rem;}}@media (min-width:740px){.css-w739ur{font-size:1.25rem;line-height:1.4375rem;}}.css-9s9ecg{margin-bottom:15px;}.css-16ed7iq{width:100%;display:-webkit-box;display:-webkit-flex;display:-ms-flexbox;display:flex;-webkit-align-items:center;-webkit-box-align:center;-ms-flex-align:center;align-items:center;-webkit-box-pack:center;-webkit-justify-content:center;-ms-flex-pack:center;justify-content:center;padding:10px 0;background-color:white;}.css-pmm6ed{display:-webkit-box;display:-webkit-flex;display:-ms-flexbox;display:flex;-webkit-align-items:center;-webkit-box-align:center;-ms-flex-align:center;align-items:center;}.css-pmm6ed > :not(:first-child){margin-left:5px;}.css-5gimkt{font-family:nyt-franklin,helvetica,arial,sans-serif;font-size:0.8125rem;font-weight:700;-webkit-letter-spacing:0.03em;-moz-letter-spacing:0.03em;-ms-letter-spacing:0.03em;letter-spacing:0.03em;text-transform:uppercase;color:#333;}.css-5gimkt:after{content:’Collapse’;}.css-rdoyk0{-webkit-transition:all 0.5s ease;transition:all 0.5s ease;-webkit-transform:rotate(180deg);-ms-transform:rotate(180deg);transform:rotate(180deg);}.css-eb027h{max-height:5000px;-webkit-transition:max-height 0.5s ease;transition:max-height 0.5s ease;}.css-6mllg9{-webkit-transition:all 0.5s ease;transition:all 0.5s ease;position:relative;opacity:0;}.css-6mllg9:before{content:”;background-image:linear-gradient(180deg,transparent,#ffffff);background-image:-webkit-linear-gradient(270deg,rgba(255,255,255,0),#ffffff);height:80px;width:100%;position:absolute;bottom:0px;pointer-events:none;}.css-uf1ume{display:-webkit-box;display:-webkit-flex;display:-ms-flexbox;display:flex;-webkit-box-pack:justify;-webkit-justify-content:space-between;-ms-flex-pack:justify;justify-content:space-between;}.css-wxi1cx{display:-webkit-box;display:-webkit-flex;display:-ms-flexbox;display:flex;-webkit-flex-direction:column;-ms-flex-direction:column;flex-direction:column;-webkit-align-self:flex-end;-ms-flex-item-align:end;align-self:flex-end;}.css-12vbvwq{background-color:white;border:1px solid #e2e2e2;width:calc(100% – 40px);max-width:600px;margin:1.5rem auto 1.9rem;padding:15px;box-sizing:border-box;}@media (min-width:740px){.css-12vbvwq{padding:20px;width:100%;}}.css-12vbvwq:focus{outline:1px solid #e2e2e2;}#NYT_BELOW_MAIN_CONTENT_REGION .css-12vbvwq{border:none;padding:10px 0 0;border-top:2px solid #121212;}.css-12vbvwq[data-truncated] .css-rdoyk0{-webkit-transform:rotate(0deg);-ms-transform:rotate(0deg);transform:rotate(0deg);}.css-12vbvwq[data-truncated] .css-eb027h{max-height:300px;overflow:hidden;-webkit-transition:none;transition:none;}.css-12vbvwq[data-truncated] .css-5gimkt:after{content:’See more’;}.css-12vbvwq[data-truncated] .css-6mllg9{opacity:1;}.css-qjk116{margin:0 auto;overflow:hidden;}.css-qjk116 strong{font-weight:700;}.css-qjk116 em{font-style:italic;}.css-qjk116 a{color:#326891;-webkit-text-decoration:underline;text-decoration:underline;text-underline-offset:1px;-webkit-text-decoration-thickness:1px;text-decoration-thickness:1px;-webkit-text-decoration-color:#326891;text-decoration-color:#326891;}.css-qjk116 a:visited{color:#326891;-webkit-text-decoration-color:#326891;text-decoration-color:#326891;}.css-qjk116 a:hover{-webkit-text-decoration:none;text-decoration:none;}And even as countries have promised to donate more doses, they have been slow to follow through, with the World Health Organization saying that only 15 percent of promised donations have been delivered. The W.H.O. has set a target of vaccinating 40 percent of every country’s population this year, requiring wealthy nations to share doses significantly more quickly.There remains considerable excess supply: Wealthy nations will have 1 billion more vaccines than they need by the end of 2021, even if they administer booster shots, according to Airfinity, a science analytics company.Global health officials have urged wealthy nations to let go of those supplies before they expire. Some countries have donated vaccines so close to their expiration dates, and in such small quantities, that poorer countries have struggled to use them.Some 11 billion doses are needed globally, and activists said on Wednesday that the wealthy world’s response remained far too piecemeal. The new Pfizer doses purchased by the U.S. will be shipped through Covax starting in January.