One in five adult Covid survivors under the age of 65 in the United States has experienced at least one health condition that could be considered long Covid, according to a large new study by the Centers for Disease Control and Prevention. Among patients 65 and older, the number is even higher: one in four.In an indication of how seriously the federal health agency views the problem of long Covid, the authors of the study — members of the C.D.C.’s Covid-19 Emergency Response Team — recommended “routine assess­ment for post-Covid conditions among persons who survive Covid-19.”Long Covid is the term used to describe an array of symptoms that can last for months or longer after the initial coronavirus infection. The researchers identified post-Covid health problems in many different organ systems, including the heart, lungs and kidneys. Other issues involved blood circulation, the musculoskeletal system and the endocrine system; gastrointestinal conditions, neurological problems and psychiatric symptoms were also identified in the study.In both age groups, Covid patients had twice the risk of uninfected people of developing respiratory symptoms and lung problems, including pulmonary embolism, the study found. Post-Covid patients aged 65 and older were at greater risk than the younger group of developing kidney failure, neurological conditions and most mental health conditions.“It is sobering to see the results of this study again confirming the breadth of organ dysfunction and the scale of the problem,” said Dr. Ziyad Al-Aly, chief of research and development at the V.A. St. Louis Health Care System and a clinical epidemiologist at Washington University in St. Louis, who was not involved in the research.The study evaluated electronic medical records for nearly two million people — comparing those who had been infected with the coronavirus with those who were not. The most common post-Covid conditions, regardless of age, were respiratory problems and musculoskeletal pain.The risk of post-Covid patients aged 65 and older developing the 26 health conditions the study evaluated was between 20 percent and 120 percent greater than people who didn’t get Covid. Those aged 18 to 64 had a 10 percent to 110 percent greater risk than uninfected people of developing 22 of the health conditions. But in that age group, Covid survivors were no more likely than uninfected people to develop most mental health conditions, substance use disorders or strokes and similar cerebrovascular conditions.Dr. Al-Aly said the study results “can potentially translate into millions of people with new diabetes, heart disease, kidney disease, neurologic problems. These are lifelong conditions — certainly manageable, but not curable conditions.”The study analyzed records of 353,164 people who were diagnosed with Covid-19 in the first 18 months of the pandemic, beginning in March 2020. It compared them with the records of 1.64 million people who had a medical visit in the same month in which the Covid patients were diagnosed but did not become infected with the coronavirus during the study period, which ended on Oct. 31, 2021.People in both groups who had a history of one of the 26 health conditions in the previous year were excluded from the study — an attempt by the researchers to consider medical issues that patients developed only after they had Covid.The study, which involved patients seen at health facilities that use a record system managed by Cerner Corp., a large medical data company, said the Covid patients included people admitted to hospitals, seen in emergency departments or diagnosed in an outpatient setting. The researchers did not indicate how many patients were in each group, one of several limitations of the study’s findings.Between 30 days and 365 days after their coronavirus diagnosis, 38 percent of the patients experienced one or more new health problems, compared to 16 percent of the non-Covid patients, the study said. The younger age group, 18-to-64, was somewhat less likely to have those problems — 35 percent developed long Covid issues, compared with 15 percent of uninfected people. In the 65-and-older group, 45 percent had new health conditions, compared with 19 percent of uninfected people.Based on those percentages, the study authors calculated that nearly 21 percent of the younger group and nearly 27 percent of the older group developed health problems that could be attributed to long Covid.The study did not look at the vaccination status of the patients and did not report characteristics like race, ethnicity, sex or geographic location. It also did not identify which coronavirus variants were linked to each case.The C.D.C. authors concluded that post-Covid conditions might “affect a patient’s ability to contribute to the work force and might have economic consequences for survivors and their dependents.” They added that “care requirements might place a strain on health services” in “communities that experience heavy Covid-19 case surges.”Dr. Al-Aly said he agreed that people who had Covid should be medically evaluated for potential new health problems.“Now that we are in possession of knowledge that Covid-19 can lead to serious long-term consequences,” he added, “we need to develop additional tools to reduce the risk of long Covid.”

Maybe, according to a growing number of studies, but there’s not yet a definitive answer.As the pandemic enters its third year, long Covid has emerged as an increasingly important concern. And many people are wondering whether getting a Covid shot can reduce their chances of developing long-term symptoms.What does the research show so far?The jury is still out, but a growing number of studies suggest that getting a Covid vaccine can reduce — though not eliminate — the risk of longer-term symptoms.The United Kingdom’s Health Security Agency conducted an analysis of eight studies that had been published on the topic before mid-January. It reported that six of the studies found that vaccinated people who became infected with the coronavirus were less likely than unvaccinated patients to develop symptoms of long Covid. The remaining two studies found that vaccination did not appear to conclusively reduce the chances of developing long Covid.How much protection could vaccines offer, according to the studies that found benefit?Some study results suggest substantial protection, while others find only a slight benefit.One large study of electronic records of patients in the U.S. Veterans Health Administration found that vaccinated Covid patients had only a 13 percent lower risk than unvaccinated patients of having symptoms six months later.Two studies in Britain found a bigger effect. One study of about 1.2 million people, based on patients’ reports via a phone app, found a 50 percent lower risk of lingering symptoms among vaccinated patients. Another, which has not been peer-reviewed and was based on surveying about 6,000 patients, found a 41 percent lower risk.A study of U.S. patients by Arcadia, a health care data firm, and the Covid Patient Recovery Alliance, a collaboration of leaders with health expertise in government and the private sector, found a larger benefit still. The study, which has not been peer-reviewed, analyzed records of about 240,000 patients infected with the coronavirus by May 2021 and found that those who had received even one dose of a Covid vaccine before their infection were one-seventh to one-tenth as likely to report two or more symptoms of long Covid 12 to 20 weeks later. That study also found that people who received their first vaccine dose after contracting the coronavirus were less likely to develop long Covid than those who remained unvaccinated, and the sooner they were vaccinated after infection, the lower the risk of long-term symptoms.A study in Israel, which has also not been peer-reviewed, found through surveys that people who received two doses of vaccine had between 54 percent and 82 percent lower risk than unvaccinated patients to report having seven of the 10 most common long-term symptoms. They were generally no more likely to report symptoms like headache, muscle pain and other issues than people in the general population who had never gotten Covid, the study said. (The authors said they could not confirm whether the patients were vaccinated before or after they had gotten Covid, but said that because of Israeli vaccination policy it was likely most people who received two doses of vaccine were infected with the coronavirus sometime after they had gotten their shots.)In the veterans’ study, also not yet published in a peer-reviewed publication, researchers compared about 48,000 patients who were unvaccinated when they got Covid with about 16,000 patients who were vaccinated. It found that vaccinated patients mostly benefited by being less likely to develop lung problems and blood-clotting difficulties, said one of the authors, Dr. Ziyad Al-Aly, chief of research and development at the V.A. St. Louis Health Care System and a clinical epidemiologist at Washington University in St. Louis. Other symptoms showed “very little risk reduction” from vaccines, he said.“The overall message is that vaccines reduce but do not eliminate the risk of long Covid,” said Dr. Al-Aly, adding that “reliance on vaccination as a sole mitigation strategy is wholly inadequate. It is like going to battle with a shield that only partially works.”A long-Covid patient was examined in a hospital in Tel Aviv in February.Amir Cohen/ReutersWhat about studies that don’t show any benefit?In an analysis of electronic medical records of patients in the United States, researchers in the United Kingdom compared about 10,000 people who had received Covid vaccines with a similar number of people who had not been vaccinated against the coronavirus but had received a flu vaccine — an effort to limit the number of people in the study who might be considered vaccine hesitant or who generally had less healthy behaviors.The study found that having a coronavirus vaccine before being infected did not reduce the risk of most symptoms of long Covid. There was some suggestion from the data that vaccinated people might be at lower risk of long-term symptoms like abnormal breathing and cognitive issues, the authors wrote, but those results were not statistically conclusive.The researchers said it was possible that because their data relied on electronic health records, the study might have captured only patients with the most severe symptoms, rather than a wider range of patients who did not seek medical attention for their symptoms.Why is the research conflicting?One reason is the differences in the studies themselves. Not all researchers have defined long Covid in the same way, measured the same symptoms or tracked patients for the same length of time. For example, some studies recorded symptoms that have lingered at least 28 days after infection, while others measured symptoms people were experiencing six months later. Studies relying on patient surveys may yield very different results than those based on electronic medical records. And some studies did not have very diverse populations. Patients in the veterans’ study, for example, were mostly older, white and male.Are the results different for different coronavirus variants?Much of the published data followed patients infected early in the pandemic. Some recently-published data included people infected by the highly contagious Delta variant, but it is too early for studies about vaccines and long Covid that include the Omicron variant. It’s also too early for studies evaluating the effect of boosters on long Covid.Is there anything scientists can conclude for sure?Yes. Vaccines are very effective at preventing people from getting seriously ill from infection by all the variants known so far. And many studies have found that Covid patients sick enough to be hospitalized were more likely to have lasting health issues. So, by keeping people out of the hospital, vaccines should reduce the chances of that type of long-term post-Covid case.Still, many people with long Covid had mild or even asymptomatic initial infections, and while some studies suggest vaccines have potential to ease their long-term symptoms, the evidence is not yet conclusive.Vaccines do offer some protection against getting infected to begin with — and avoiding infection, of course, is the surest way to prevent long Covid.Does the brand of vaccine make a difference in potential protection against long Covid?So far, studies have not found that different vaccines have different effects on long-term symptoms.What are the possible scientific reasons that vaccines might protect against long Covid?The cause of long Covid is still unclear, and different symptoms might have different underlying causes in different patients, scientists say. Some believe that the condition may be related to remnants of the virus or its genetic material lingering after the initial infection subsides. Another theory is that the continuing problems are related to inflammation or blood circulation problems spurred by an overactive immune response that is unable to shut down.Akiko Iwasaki, an immunologist at Yale, has said that vaccines may be able to provide lasting relief in people whose symptoms are caused by vestiges of the virus if the antibodies generated by the vaccines eliminate those remnants.But in people whose symptoms may be caused by a post-viral response resembling an autoimmune disease, she said, vaccines may help only temporarily, and problems like fatigue could re-emerge.One thing we know for certain is that vaccines are very effective at preventing people from getting seriously ill from infection by all the variants known so far. Kenny Holston for The New York TimesCan getting vaccinated help if you already have long Covid?When vaccines were first rolled out, some patients with long Covid were finding that symptoms like brain fog, joint pain, shortness of breath and fatigue improved after they had gotten vaccinated. Still, many people experienced no difference in their symptoms after vaccination, and a small percentage said they felt worse.A study by the Office for National Statistics in the United Kingdom found that in people ages 18 to 69 who reported their symptoms between February and September 2021, a first dose of a vaccine lowered the odds of reporting long Covid symptoms by 13 percent. A second dose further lowered the odds by 9 percent, the study found.The recent analysis by the U.K. Health Security Agency evaluated that study and seven others that examined whether vaccinating people with long Covid affected their symptoms. It found that in most of those studies, more people with long Covid reported improvement in their symptoms at some point after they were vaccinated. However, some people also reported worsening of symptoms, and in several studies the majority of people said their symptoms were unchanged.The agency noted that the definition of long Covid varied widely among the studies and that, because all the studies were observational, changes in symptoms could be due to factors other than vaccination.

Officials cited data showing the new Alzheimer’s drug has serious safety risks and may not help patients.For the past few months, Medicare officials have been inundated with impassioned pleas about how to handle coverage of the controversial new Alzheimer’s drug Aduhelm.Advocacy groups for patients have said the federal insurance program for people 65 and over must pay for a drug approved by the Food and Drug Administration. Many Alzheimer’s doctors and experts cautioned against broadly covering a treatment that scientific evidence shows has uncertain benefit and serious safety risks. Individual patients and families weighed in on both sides with emotional statements.On Thursday, Medicare officials announced their final decision. The program will cover Aduhelm only if people receive it as participants in a clinical trial, likely a small percentage of the estimated 1.5 million people in the United States who have mild Alzheimer’s-related cognitive decline, the condition Aduhelm was approved to treat.Chiquita Brooks-LaSure, the administrator of the Centers for Medicare and Medicaid Services said the decision was intended to protect patients while gathering data to indicate whether Aduhelm, an expensive monoclonal antibody given as a monthly infusion, could actually help them by slowing the pace of their cognitive decline.“It’s our obligation at C.M.S. to really make sure it’s reasonable and necessary,” Ms. Brooks-LaSure said in an interview Thursday. “The vast majority” of the approximately 10,000 comments the agency received on its website, she said, were in favor of “really limiting coverage of Aduhelm to a really controlled space where we could continue to evaluate its appropriateness for the Medicare population.”A major issue for Medicare had been how to deal with other similar drugs for Alzheimer’s, several of which are likely to be considered for F.D.A. approval soon. In a proposal in January, C.M.S. had said it would cover them in the same way as Aduhelm because it typically made coverage decisions for an entire class of drugs.People in favor of wider access to Aduhelm held a rally outside the Department of Health and Human Services last month.Kenny Holston for The New York TimesBut after both experts and advocacy groups raised concerns, Medicare officials said Thursday that they would not automatically apply the same restrictions to each new drug. If, unlike with Aduhelm, the F.D.A. finds that there is clear evidence that a drug can help patients, Medicare would cover it for all eligible patients and would only impose a requirement that the patients’ experience be tracked.Dr. Lee Fleisher, the chief medical officer at C.M.S., said the two-track way of dealing with the fast-developing field of Alzheimer’s therapies, a program called Coverage with Evidence Development, “is meant to be nimble and really respond to any new drugs in this class that are in the pipeline, and do demonstrate clinical benefit.”The decision is extremely unusual for Medicare, which almost always automatically pays for drugs that the F.D.A. has approved, at least for the medical conditions designated on labels. Understand the New Alzheimer’s Drug AduhelmF.D.A. Approval: In a contentious decision, the agency approved the first new Alzheimer’s treatment in nearly two decades. A Fierce Debate: Alzheimer’s patients are desperate for new options, but some scientists say there isn’t enough evidence Aduhelm works.Potential Safety Risks: Concerns over Aduhelm intensified after a 75-year-old woman in a clinical trial developed brain swelling and died.Medicare Limits: Officials said the federal program should cover the drug only for patients who are participating in approved clinical trials.The Campaign for Coverage: A powerful Alzheimer’s advocacy group is pushing relentlessly for broad Medicare access to the drug.But Aduhelm’s path has been very unusual, too. The F.D.A. itself acknowledged that it was unclear if the drug was beneficial when it approved Aduhelm last June. It greenlighted the drug under a program called “accelerated approval,” which allows authorization of drugs that have uncertain benefit if they are for serious diseases with few treatments and if the drug affects a biological mechanism in a way considered reasonably likely to help patients.The clinical trial evidence reviewed by the F.D.A. showed that patients in one trial appeared to experience slight slowing of cognitive decline, while patients in a nearly identical trial didn’t appear to benefit at all. About 40 percent of patients on the dosage later approved experienced brain swelling or brain bleeding, often mild, but sometimes serious. Both a council of senior F.D.A. officials and the agency’s independent advisory committee had said there wasn’t enough evidence for approval.The drug, manufactured by Biogen, takes the form of a monthly intravenous infusion.Pool photo by Jessica RinaldiQuestions about the approval, and whether the F.D.A. worked too closely with Biogen, Aduhelm’s manufacturer, have prompted investigations by congressional committees, the Health and Human Services department’s inspector general, the Federal Trade Commission and the Securities and Exchange Commission. Major medical centers, including the Cleveland Clinic, have declined to offer Aduhelm. As a result of concerns raised by Alzheimer’s experts and some groups, Medicare officials announced several other changes to their earlier proposal. Instead of requiring randomized controlled trials approved by C.M.S., Medicare will cover participants in any trial approved by the F.D.A. or the National Institutes of Health. It will allow those trials to be conducted in a broader array of locations, not just hospital settings, and to include people with other neurological conditions like Down syndrome, many of whom develop Alzheimer’s but had been excluded from the earlier proposed plan.The trials will still need to comply with a Medicare requirement to recruit a racially and ethnically diverse group of participants, contrasting with the previous trials of Aduhelm, in which most participants were white.In the trials, “the manufacturers will have to come to us with how are they going to include all patients that represent the Medicare population, and how are they going to ensure that all of these patients are getting appropriate medical treatment and monitoring of their treatment while they’re in each of these studies,” Tamara Syrek Jensen, the director of coverage and analysis for C.M.S.’s Center for Clinical Standards and Quality, said in an interview.The F.D.A. has also required Biogen to conduct another clinical trial to determine if the drug provided any evidence of benefit, but it said that in the years it will take for that trial to be completed, Aduhelm would be available to patients. Under Thursday’s decision, Medicare would cover the costs for participants in Biogen’s trial. Medicare’s coverage evaluation team makes decisions without considering the cost of a drug, but the Aduhelm decision could ease some concerns about how covering the drug might affect the pocketbooks of the country’s millions of Medicare beneficiaries.Counterprotesters at the Aduhelm rally in Washington in March.Kenny Holston for The New York TimesLast year, Medicare’s actuarial division, acting without knowing what the coverage decision would be, imposed one of the biggest-ever increases in Medicare Part B premiums for 2022, partly driven by the possibility of coverage for Aduhelm, which at the time was priced by its manufacturer at $56,000 a year.Since then, Biogen, facing weak sales of the drug after many hospitals and doctors would not prescribe it, lowered the price to $28,800 a year, still much higher than many analysts have said is warranted.Xavier Becerra, secretary of health and human services, had said that he would consider lowering premiums after the final coverage decision for Aduhelm was made, adding that “We’re going to make sure that seniors don’t pay more than they have to.”In the interview Thursday, Ms. Brooks-LaSure, the C.M.S. administrator, said “The secretary told us to look at it, and we are going to engage in the process of reviewing the Part B premium.”Advocacy groups, several of which receive some funding from Biogen and other pharmaceutical companies, had campaigned vigorously for broad Medicare coverage. These groups said patients should be able to decide with their doctors whether to try an F.D.A.-approved drug and claimed it was discriminatory to only reimburse participation in clinical trials that may not be easily accessible to many patients.“We just can’t let it stand as it is,” Harry Johns, the chief executive of the Alzheimer’s Association, told the organization’s staff, according to a recording of the meeting obtained by The New York Times.In an interview before the Medicare announcement, Mr. Johns indicated that the association wouldn’t be satisfied if Medicare’s restrictions applied only to Aduhelm, saying, “We absolutely believe there is sufficient evidence to provide coverage for the first approved treatment.”

The Alzheimer’s Association has pushed relentlessly to get broad access to Aduhelm, despite safety risks and uncertain evidence that it helps patients.The day after Medicare officials announced a preliminary decision to sharply limit coverage of the controversial new Alzheimer’s medication Aduhelm, citing its unclear benefit and serious safety risks, the nation’s most prominent Alzheimer’s advocacy organization convened its policy team.The agenda: fighting Medicare’s proposal.“This is our top priority,” Robert Egge, the association’s chief public policy officer, said at the Jan. 12 session, according to recordings obtained by The New York Times.The next day, the chief executive, Harry Johns, took the mission to the entire staff, saying, “You can count on us being relentless.”Medicare’s proposal to pay for Aduhelm only for participants in randomized clinical trials was welcomed by many Alzheimer’s experts and other doctors. They say it would protect patients and families whose desperation might lead them to try anything, while also rigorously evaluating whether Aduhelm actually works.But the Alzheimer’s Association and similar groups, along with Aduhelm’s manufacturer, Biogen, strongly object. They say that Aduhelm, a monoclonal antibody that is the first drug approved for Alzheimer’s in 18 years, should be covered for anyone with mild Alzheimer’s-related cognitive decline and that usage decisions should rest with patients and their doctors.The association’s campaign makes little mention of Aduhelm’s safety risks and uncertain benefit, arguing that restricting coverage of an F.D.A.-approved drug is “shocking discrimination against everyone with Alzheimer’s disease.”With Medicare’s final decision due by April 11, the group has organized tweets directed at President Biden, emails directed at Congress, and ads on social media and websites including Univision, Essence and Martha Stewart.It has orchestrated over 400 meetings in which people with Alzheimer’s, their family members or supporters have implored their members of Congress to press the Centers for Medicare and Medicaid Services (C.M.S.) to broadly cover the drug. In sessions prepping for those meetings, association officials suggested that people say versions of phrases like “I have a fatal disease and I want more time with my family” and to discuss “how access to F.D.A.-approved treatments will impact me and my family.”Leaders also encouraged people to submit comments to C.M.S. in ways that weren’t scripted. “It is important that individuals not use our talking points,” Beth McMullen, senior director of grassroots advocacy, instructed at one meeting. Employees filing comments “cannot submit as a staff member of the Alzheimer’s Association,” she said.The push reflects growing activism by advocacy groups involved in various diseases, which sometimes campaign for therapies despite medical experts’ concerns about insufficient data. Some are partially funded by pharmaceutical companies. In fiscal year 2021, the Alzheimer’s Association received $1.6 million from manufacturers developing monoclonal antibodies, including $487,500 from Biogen.Biogen, Aduhelm’s manufacturer, gave the Alzheimer’s Association $487,500 in fiscal year 2021.C.J. Gunther/EPA, via ShutterstockOther Alzheimer’s advocacy groups are also campaigning, including UsAgainstAlzheimer’s. It has run television ads featuring patients and has written in strident language to C.M.S. that “the government would be consigning millions of Americans to inevitable decline and death, with no possibility of appeal.” The Alliance for Aging Research led a rally of about 100 people outside the Department of Health and Human Services, which houses C.M.S. (Afterward, about half the alliance’s scientific advisory board quit in opposition to the group’s position.)Understand the New Alzheimer’s Drug AduhelmF.D.A. Approval: The agency approved the first new Alzheimer’s treatment in 18 years despite fierce debate over whether it works.Potential Safety Risks: Concerns over Aduhelm intensified after a 75-year-old woman in a clinical trial developed brain swelling and died.Medicare Limits: Officials said the federal program should cover the drug only for patients who are participating in approved clinical trials.Understand Alzheimer’s: Get answers to common questions about the disease, which affects about 30 million people globally.Medicare’s coverage proposal came after Aduhelm, an expensive monthly infusion that also has the scientific name aducanumab, was approved in June by the Food and Drug Administration despite contradictory scientific results. Participants in one clinical trial appeared to experience slight slowing of cognitive decline, while patients in a nearly identical trial didn’t appear to benefit at all. About 40 percent of patients on the dosage later approved experienced brain swelling or brain bleeding, often mild, but sometimes serious. Both a council of senior F.D.A. officials and the agency’s independent advisory committee had said there wasn’t enough evidence for approval. Questions about the approval, and whether the F.D.A. worked too closely with Biogen, have prompted investigations by congressional committees, the Health and Human Services department’s inspector general, the Federal Trade Commission and the Securities and Exchange Commission. Major medical centers, including the Cleveland Clinic, have declined to offer Aduhelm.After C.M.S. announced its proposal, Dr. Lee Fleisher, the agency’s chief medical officer, said, “Our foremost goal is to protect beneficiaries from potential harm from an intervention without known benefits in the Medicare population.”The proposal has attracted extraordinary interest, with C.M.S. receiving 9,957 comments, some organized by advocacy groups on both sides of the debate.The Alzheimer’s Association, with revenue of about $400 million, is highly influential in the Alzheimer’s field: It runs an international conference, provides research grants and publishes a journal.In recordings of the staff meeting and two prep sessions, association officials didn’t mention Aduhelm’s safety risks.In an interview, Mr. Johns, the chief executive, said, “We take the safety concerns seriously,” adding, “The risks are real, but they’re not worse than treatments that are covered by Medicare today.” He proposed that patients enroll in a registry where negative effects could be reported. But many experts say that wouldn’t sufficiently evaluate the drug. At the staff meeting, Maria Carrillo, the association’s chief science officer, addressed issues of whether Aduhelm works by saying, “One of the questions that you may be asked, or maybe you’re asking yourself is: Is the scientific evidence sufficient to conclude” that Aduhelm and similar monoclonal antibodies “improve health outcomes for Medicare beneficiaries?” The answer, she said, was “yes.”While some patients enthusiastically back the association’s efforts, its stance troubles some longtime supporters of the organization, including Dr. Daniel Gibbs, a retired neurologist in Portland, Ore., with early-stage Alzheimer’s. Dr. Daniel Gibbs, a retired neurologist with early-stage Alzheimer’s, agrees with Medicare’s proposed restrictions on Aduhelm.Amanda Lucier for The New York TimesHe participated in an aducanumab trial, experiencing brain swelling and bleeding that required treatment in an intensive care unit. “I want aducanumab to be successful, and I really think that it might be useful,” he said. However, he added, he considers Medicare’s proposed restrictions appropriate.He called the Alzheimer’s Association campaign “shocking and irresponsible” and said he’ll stop donating to the organization, except for his local chapter. “The vast majority of experts in Alzheimer’s are not on the side of the Alzheimer’s Association,” he said.Several members of the association’s scientific and medical advisory group said they had concluded the drug shouldn’t yet be approved. Still, the association pushed for approval.The F.D.A. itself acknowledged the unclear benefit when it greenlighted Aduhelm under “accelerated approval,” which allows authorization of unproven drugs for serious diseases with few treatments, if the drug affects a biological mechanism in a way considered “reasonably likely to predict clinical benefit.”The agency’s justification was that Aduhelm targets a protein, amyloid, that forms plaques in the brains of Alzheimer’s patients. But many Alzheimer’s experts say that years of data have not shown that reducing amyloid can slow cognitive decline.In the association staff meeting, Dr. Carrillo described experts who criticized Aduhelm’s approval as “naysayers” who “are mainly anti-amyloid researchers, in conflict, in my view.”Several scientists critical of Aduhelm’s approval support the idea that targeting amyloid might help patients; they simply found Aduhelm’s results unconvincing.Mr. Egge, the chief public policy officer, did say at one meeting: “It’s not certain that this first treatment will work, certainly, for everybody, but it could.” He said that it’s common to have “first treatments making marginal differences” but that later drugs often work better. Mr. Johns said the association and its lobbying affiliate, the Alzheimer’s Impact Movement, have spent hundreds of thousands of dollars on the campaign.At the staff meeting, Mr. Johns addressed another issue: “Of course, you’ll hear people claim that we’re doing this because we receive some funding from the pharmaceutical industry or these companies.”He said corporate contributions “are very small, less than 1 percent of our total revenue,” adding, “We would never be affected by any kind of fund-raising.”One attendee asked: “Since the amount of funding we receive from biotech companies is so low, why not refuse to take it and take away the appearance of possible conflicts of interest?”Mr. Johns replied, “We’ve contemplated this many times,” but concluded it would have unintended consequences, like preventing the organization from accepting corporate matching contributions for participants in association fund-raising walks who happened to work at pharmaceutical companies.In the interview, Mr. Johns echoed these explanations. Asked if association officials had communicated with Biogen since Medicare’s proposal, he said, “I think probably some of our folks have had a conversation or more along the way” and that Biogen’s staff “occasionally pass along a piece of information, but I can tell you that we just don’t coordinate with them.”In the recordings, association officials told advocates that their annual meetings with local members of Congress would involve different “asks” than usual: They should request that lawmakers give a floor speech, write to C.M.S., or post on social media to urge Medicare to broadly cover Aduhelm and any other F.D.A.-approved Alzheimer’s treatment.One official, Jennifer Pollack, suggested that advocates should give congressional staff a “leave-behind” that included a sample letter, and social media posts drafted by the association and “sample talking points for a floor speech.”Kate Johnson, another official, told advocates: “If you do not know the answer to a question, that is totally OK.” In that case, “please always revert to our safest phrase,” which, she said, was: “‘I’m not sure, but I can pass that question on to a staffer at the Alzheimer’s Association who can provide some more information.’”She also urged advocates to take photos or screenshots of the congressional meetings to post on social media, tagging the lawmaker to show “we’re not going to give up on the issues that we’re passionate about.”Christopher Masak, director of advocacy, role-played being an Alzheimer’s patient’s son meeting with a lawmaker.“My mom is living with a fatal disease, and the bottom line is, I want more time,” his character said, adding, “Thinking of people like my mom who can’t access this medication, it just, it breaks my heart.”Medicare officials said that limiting coverage to clinical trial participants is especially important because Aduhelm is intended for people with early mild disease, who could potentially be sacrificing years of remaining function and quality of life if a drug’s harms outweigh any benefit.Mr. Johns said he understood the view that “risk could be better tolerated later in the disease” but said that the milder early period is the time many people most want to try to extend. C.M.S. officials also said Aduhelm data isn’t sufficiently representative because most trial participants were white, while Blacks and Latinos have greater Alzheimer’s risk. So, Medicare’s proposal requires that new clinical trials reflect racial and ethnic diversity.Association officials said Medicare’s proposal could have the opposite effect because people in underserved communities might have less access to clinical trial sites.A few issues mentioned by advocacy groups have also been raised by those who don’t oppose limiting coverage for Aduhelm. One is that, as currently worded, Medicare’s decision would apply to all monoclonal antibodies for Alzheimer’s, several of which are in late-stage trials and may soon be considered for F.D.A. approval.“It is essentially denying access to all current and future F.D.A.-approved treatments targeting amyloid in those living with Alzheimer’s disease,” Ms. Pollack said in one recording.The American Academy of Neurology wrote to C.M.S. calling the proposal to cover only patients in clinical trials “prudently designed to investigate the safety and effectiveness,” but asked that it be limited only to Aduhelm. In a statement, a C.M.S. spokeswoman, Beth Lynk, said coverage criteria could be re-evaluated for subsequent monoclonal antibodies. “C.M.S. intends to be nimble and respond to new evidence as it is made available — especially related to the clinical benefit of future therapeutics,” she said.Mr. Johns, who said that he recently attended three meetings with C.M.S. officials, including one with the agency’s administrator, indicated in the interview that the association wouldn’t be satisfied if Medicare’s restrictions applied only to Aduhelm, saying, “We absolutely believe there is sufficient evidence to provide coverage for the first approved treatment.”Advocacy groups’ efforts have gotten some lawmakers’ attention. Recently, a bipartisan group of 40 House members wrote asking C.M.S. to provide broad coverage.Earlier, 78 House Republicans sent a letter criticizing C.M.S.’s proposal, quoting the Alzheimer’s Association and UsAgainstAlzheimer’s. Both advocacy groups were described on Senator Susan Collins’s website as supporting a letter she and another Republican, Senator Shelley Moore Capito, wrote.Some lawmakers, including Democrats, have tweeted a version of the association’s language.But other lawmakers praised Medicare’s proposal, including Representatives Carolyn B. Maloney and Frank Pallone, Democrats who chair committees investigating the F.D.A.’s approval of Aduhelm.Mr. Johns said he didn’t know of any lawmakers who had switched from supporting to opposing Medicare’s proposal. But he said the association’s congressional meetings “have had positive outcomes, even for people who might still have a different opinion. There is at least a different level of understanding.”He declined to provide the number of tweets, letters or other measures of the campaign’s reach, saying: “There are those who are working against access. We are not inclined to share details of our tactical approaches with them. Our activities will be measured by outcomes that grant those with Alzheimer’s disease access to current and future F.D.A.-approved treatments without unnecessary barriers.”

Covid-19 may cause greater loss of gray matter and tissue damage in the brain than naturally occurs in people who have not been infected with the virus, a large new study finds.The study, published Monday in the journal Nature, is believed to be the first involving people who underwent brain scans both before they contracted Covid and months after. Neurological experts who were not involved in the research said it was valuable and unique, but they cautioned that the implications of the changes were unclear and did not necessarily suggest that people might have lasting damage or that the changes might profoundly affect thinking, memory or other functions.The study, involving people aged 51 to 81, found shrinkage and tissue damage primarily in brain areas related to sense of smell; some of those areas are also involved in other brain functions, the researchers said.“To me, this is pretty convincing evidence that something changes in brains of this overall group of people with Covid,” said Dr. Serena Spudich, chief of neurological infections and global neurology at the Yale School of Medicine, who was not involved in the study.But, she cautioned: “To make a conclusion that this has some long-term clinical implications for the patients I think is a stretch. We don’t want to scare the public and have them think, ‘Oh, this is proof that everyone’s going to have brain damage and not be able to function.’”

The data, released in a report Thursday, is a sign that medication abortion has become the most accessible and preferred method for terminating pregnancy.More than half of recent abortions in the United States were carried out with abortion pills, according to preliminary data released on Thursday, a sign that medication abortion has increasingly become the most accessible and preferred method for terminating pregnancy.The report, issued by the Guttmacher Institute, a research organization that supports abortion rights, found that in 2020, medication abortion — a two-pill method authorized in the United States for pregnancies up to 10 weeks’ gestation — accounted for 54 percent of all abortions. The figure represents a substantial increase from the institute’s previous report, which found that the method accounted for 39 percent of abortions in 2017.The increase in medication abortion is most likely the result of several factors. The method — which is less expensive and less invasive than surgical abortions — had already become increasingly common before the coronavirus pandemic, driven partly by restrictions from conservative states that imposed hurdles to surgical methods, especially later in pregnancy.As of 2017, according to the Guttmacher Institute, which collects data by contacting every known abortion provider in the country, nearly a third of clinics offered only medication abortion. In 2019, according to data from the Centers for Disease Control and Prevention, which did not include California, Maryland and New Hampshire, pills accounted for 42 percent of all abortions — and 54 percent of abortions that were early enough to qualify for medication because they occurred before 10 weeks’ gestation.The pandemic fueled that trend, as medical groups filed a lawsuit asking the federal government to lift the Food and Drug Administration’s requirement that the first of the two abortion pills, mifepristone, be dispensed to patients in person at a clinic or doctor’s office. Citing years of data showing that medication abortion is safe, the medical groups said that patients faced a greater risk of being infected with the coronavirus if they had to visit clinics to obtain mifepristone and pointed out that mifepristone was the only drug that the F.D.A. required patients to get in person from a medical provider but that patients were also allowed to take at home on their own without having the provider present.A judge granted the request that summer, allowing patients to see a physician by telemedicine and receive pills by mail, but, after a challenge by the Trump administration, the Supreme Court reinstated the restriction early last year.Under the Biden administration, however, the F.D.A. permanently lifted the in-person requirement in December and also said that pharmacies could begin dispensing mifepristone if they met certain qualifications. The F.D.A.’s action means that medication abortion will become more available to women who find it difficult to travel to an abortion provider or prefer the privacy of being able to terminate a pregnancy in their homes.As a result, while the new report from the Guttmacher Institute is preliminary — only reflecting information from 75 percent of the clinics and including only percentages, not raw data — the proportion of abortions carried out with pills is expected to increase further.Nearly 80 percent of all abortions in the C.D.C.’s 2019 data occurred before 10 weeks’ gestation, suggesting that there were many more women who might choose abortion pills over an in-clinic procedure if they could.At the same time, the growing interest in medication abortion has made it a focus of the highly polarized abortion debate.In 19 states, mostly in the South and the Midwest, telemedicine visits for medication abortion are banned, and so far in 2022, according to the Guttmacher Institute report, 16 state legislatures have introduced bills to ban or limit medication abortion.With the Supreme Court now considering whether to roll back abortion rights or even overturn the 1973 Roe v. Wade decision, which legalized abortion, experts and advocates on all sides expect medication abortion to play an even more pivotal role in the divisive abortion debate.

Though public health experts have long advised the use of condoms for anal sex to protect against H.I.V. and other infections, regulators did not have enough data to allow marketing for that use.For the first time, U.S. regulators have officially authorized a condom to be used for anal sex, not just vaginal sex.The decision, announced by the Food and Drug Administration on Wednesday, has long been sought by sexual health experts, who said it could encourage more people who engage in anal sex to use condoms to protect themselves against H.I.V. and other sexually transmitted infections.The risk of sexually transmitted diseases is “significantly higher” during anal sex than vaginal sex, an F.D.A. official said Wednesday. But until now, there has not been enough data to show that condoms are safe and effective during anal sex.“The F.D.A.’s authorization of a condom that is specifically indicated, evaluated and labeled for anal intercourse may improve the likelihood of condom use during anal intercourse,” Courtney Lias, director of the F.D.A. office that issued the approval, said in a statement. The decision applies to a condom manufactured by Global Protection Corp. called the ONE male condom. Last year, the company asked the F.D.A. to allow it to add anal sex to the intended use of the condom on the product label, based on a study showing the failure rate, defined as slippage or breakage, to be less than 1 percent during anal sex.The F.D.A. said in the statement that other condom companies would now be able to apply for similar approval by submitting claims that their condoms demonstrated “substantial equivalence” to the evidence shown for ONE condoms.“I don’t think this is viewed as something that should be restricted, but rather something that opens the door for other companies to rigorously assess their condoms and show that they also perform well for anal sex,” said Aaron Siegler, an epidemiologist at Emory University who helped lead the study that prompted the F.D.A. decision.Davin Wedel, president and founder of Global Protection Corp, said, “I think most people would be surprised to know that condoms are not approved for anal sex. With this new designation from the FDA, consumers will have important information about the safety and effectiveness of condoms for anal sex.”The federal agency had previously said that condoms needed to have less than a 5 percent failure rate, and earlier studies of condoms for anal sex had shown failure rates higher than that.As a result, while using condoms for anal sex is recommended by public health authorities like the World Health Organization and the Centers for Disease Control and Prevention, it has been considered an “off-label” use in the United States. Companies have not been able to market condoms for anal sex, said Dr. Kenneth Mayer, the medical research director for Fenway Health, a community health center in Massachusetts that has long been a leader in treating patients who identify as L.G.B.T.Q.“It’s a great thing if the package inserts could indicate anal sex because it might create an incentive for the companies to do more marketing,” Dr. Mayer said. “You don’t see condom ads on gay social media, for example, so this would incentivize that as part of part of the conversation.”“And it’s not just gay men.” Dr. Mayer continued. “It’s not that heterosexuals who engage in anal sex are unaware that condoms exist, but there’s been very little education, so it’s somewhat out of sight out of mind.”Condom use during anal sex has declined in recent years, since the advent of a method to prevent H.I.V. infection called pre-exposure prophylaxis, or PrEP, which involves taking a daily pill. According to the most recent statistics from C.D.C.’s National H.I.V. Behavioral Surveillance data, about 46 percent of men who have sex with men were having anal sex without condoms in 2017, compared to 28-to-40 percent in 2011.But although PrEP is very effective, there can be issues with cost and access. Currently, only about a third of men who are at high risk for H.I.V. infection are taking the drug, the C.D.C. reported.“That’s hundreds of thousands of people,” said Dr. Mayer, who was not involved in the study that led to the F.D.A.’s decision. “And certainly those are individuals who would benefit from condoms.”He added that condoms are the most effective protection against other sexually transmitted infections, including syphilis, which has been increasing in the United States.To try to amass data that could lead to the approval of condoms for anal sex, the company teamed up with researchers at Emory University, met with the F.D.A. and designed a study.Funded by the National Institutes of Health, the study, the largest to date on condom effectiveness during anal sex, was conducted between May 2016 and May 2017. It involved 504 men, half of whom had sex with men and half of whom had sex with women, and the researchers took several steps designed to encourage more consistent and accurate data than previous studies, Dr. Siegler said.After being trained in proper condom use, the men were given condoms and asked to fill out a daily diary on a phone app, to answer questions about whether they had had sex that day and whether the condom they used broke or slipped. The participants reported 2,351 anal and 2,533 vaginal sex acts during the study period.Dr. Siegler said that the team had hypothesized that the condom failure rate during anal sex would be low enough to pass muster with the F.D.A., but had not expected it to be as low as it was — 0.7 percent — or that it would be lower than the failure rate during vaginal sex, which was 1.9 percent.The researchers attribute the higher failure rate during vaginal sex to the fact that the study encouraged lubricant appropriate for condoms to be used for every instance of anal sex, but, adhering to public health guidelines, only encouraged lubricant to be used during vaginal sex “as needed or desired.” So, while 98 percent of people who had anal sex used lubricant, only 42 percent of those who had vaginal sex did. When the researchers looked only at people who used lubricant, the failure rate in the vaginal group was 1.1 percent, making the odds of failure in each group essentially the same, the study reported.Public health experts said that suggests that lubricant was critical to the study’s results, and in its statement, the F.D.A. said that during anal sex, the condom “should be used with a condom-compatible lubricant.”The study involved three different types of the One condom — standard, thin and fitted, which comes in 54 different sizes. They did not have ribbing or other characteristics, Dr. Siegler said. Each participant was given five samples of each type of condom to use for two to four weeks. The researchers had expected the fitted condoms to have the lowest failure rate, but the study found there was no difference, an outcome that Dr. Siegler said he thought reflected that all three varieties had to meet the same manufacturing and durability standards.Dr. Siegler, who specializes in research on PReP, said that before conducting the condom study, the Emory team wondered whether adding anal sex to a condom label would encourage more men to use condoms.“Does this matter? Would it change use?” he asked. The team conducted a survey of more than 10,000 men who had sex with men and found that 69 percent said that if the F.D.A. approved condoms for anal sex, they would be more encouraged to use them.“I don’t see condoms versus PReP as kind of mutually exclusive options, I see them as options that can support each other and that allow people that choice,” he said. “There isn’t perfect use of any one technology. But if we optimize people’s access to and understanding of different prevention options, I think we can increase the overall population level protection against H.I.V.”Dr. Mayer said he also saw adding the label to condoms as an additional tool that could help improve the use of all protective measures.“It’s definitely not a one-size-fits-all kind of kind of environment,” Dr. Mayer said. “It will help normalize the conversation because there’ll be an economic incentive for the companies to advertise condoms for anal sex.”

Social isolation, economic stress, loss of loved ones and other struggles during the pandemic have contributed to rising mental health issues like anxiety and depression.But can having Covid itself increase the risk of developing mental health problems? A large new study suggests it can.The study, published Wednesday in the journal The BMJ, analyzed records of nearly 154,000 Covid patients in the Veterans Health Administration system and compared their experience in the year after they recovered from their initial infection with that of a similar group of people who did not contract the virus.The study included only patients who had no mental health diagnoses or treatment for at least two years before becoming infected with the coronavirus, allowing researchers to focus on psychiatric diagnoses and treatment that occurred after coronavirus infection.People who had Covid were 39 percent more likely to be diagnosed with depression and 35 percent more likely to be diagnosed with anxiety over the months following infection than people without Covid during the same period, the study found. Covid patients were 38 percent more likely to be diagnosed with stress and adjustment disorders and 41 percent more likely to be diagnosed with sleep disorders than uninfected people.“There appears to be a clear excess of mental health diagnoses in the months after Covid,” said Dr. Paul Harrison, a professor of psychiatry at the University of Oxford, who was not involved in the study.

A new, large study found that in the year after getting Covid, people were significantly more likely to be diagnosed with psychiatric disorders they hadn’t had than people who didn’t get infected.Social isolation, economic stress, loss of loved ones and other struggles during the pandemic have contributed to rising mental health issues like anxiety and depression.But can having Covid itself increase the risk of developing mental health problems? A large new study suggests it can.The study, published Wednesday in the journal The BMJ, analyzed records of nearly 154,000 Covid patients in the Veterans Health Administration system and compared their experience in the year after they recovered from their initial infection with that of a similar group of people who did not contract the virus.The study included only patients who had no mental health diagnoses or treatment for at least two years before becoming infected with the coronavirus, allowing researchers to focus on psychiatric diagnoses and treatment that occurred after coronavirus infection.People who had Covid were 39 percent more likely to be diagnosed with depression and 35 percent more likely to be diagnosed with anxiety over the months following infection than people without Covid during the same period, the study found. Covid patients were 38 percent more likely to be diagnosed with stress and adjustment disorders and 41 percent more likely to be diagnosed with sleep disorders than uninfected people.“There appears to be a clear excess of mental health diagnoses in the months after Covid,” said Dr. Paul Harrison, a professor of psychiatry at the University of Oxford, who was not involved in the study. He said the results echoed the emerging picture from other research, including a 2021 study on which he was an author, and “it strengthens the case that there is something about Covid that is leaving people at greater risk of common mental health conditions.”The data does not suggest that most Covid patients will develop mental health symptoms. Only between 4.4 percent and 5.6 percent of those in the study received diagnoses of depression, anxiety or stress and adjustment disorders.“It’s not an epidemic of anxiety and depression, fortunately,” Dr. Harrison said. “But it’s not trivial.”Researchers also found that Covid patients were 80 percent more likely to develop cognitive problems like brain fog, confusion and forgetfulness than those who didn’t have Covid. They were 34 percent more likely to develop opioid use disorders, possibly from drugs prescribed for pain, and 20 percent more likely to develop non-opioid substance use disorders including alcoholism, the study reported.After having Covid, people were 55 percent more likely to be taking prescribed antidepressants and 65 percent more likely to be taking prescribed anti-anxiety medications than contemporaries without Covid, the study found.Overall, more than 18 percent of the Covid patients received a diagnosis of or prescription for a neuropsychiatric issue in the following year, compared with less than 12 percent of the non-Covid group. Covid patients were 60 percent more likely to fall into those categories than people who didn’t have Covid, the study found.The study found that patients hospitalized for Covid were more likely to be diagnosed with mental health issues than those with less serious coronavirus infections. But people with mild initial infections were still at greater risk than people without Covid.“Some people always argue that ‘Oh, well, maybe people are depressed because they needed to go to the hospital and they spent like a week in the I.C.U.,’” said the senior author of the study, Dr. Ziyad Al-Aly, chief of research and development at the V.A. St. Louis Health Care System and a clinical epidemiologist at Washington University in St. Louis. “In people who weren’t hospitalized for Covid-19, the risk was lower but certainly significant. And most people don’t need to be hospitalized, so that is really the group that’s representative of most people with Covid-19.”The team also compared mental health diagnoses for people hospitalized for Covid with those hospitalized for any other reason. “Whether people were hospitalized for heart attacks or chemotherapy or whatever other conditions, the Covid-19 group exhibited a higher risk,” Dr. Al-Aly said.The study involved electronic medical records of 153,848 adults who tested positive for the coronavirus between March 1, 2020, and Jan. 15, 2021, and survived for at least 30 days. Because it was early in the pandemic, very few were vaccinated before infection. The patients were followed until Nov. 30, 2021. Dr. Al-Aly said his team was planning to analyze whether subsequent vaccination modified people’s mental health symptoms, as well as other post-Covid medical issues the group has studied.The Covid patients were compared with more than 5.6 million patients in the Veterans system who did not test positive for the coronavirus and more than 5.8 million patients from before the pandemic, in the period spanning March 2018 through January 2019. To try to gauge the mental health impact of Covid-19 against that of another virus, the patients were also compared with about 72,000 patients who had the flu during the two and a half years before the pandemic. (Dr. Al-Aly said there were too few flu cases during the pandemic to provide a contemporaneous comparison.)The researchers tried to minimize differences between groups by adjusting for many demographic characteristics, pre-Covid health conditions, residence in nursing homes and other variables.In the year after their infection, the Covid patients had higher rates of mental health diagnoses than the other groups.“It’s not really surprising to me because we’ve been seeing this,” said Dr. Maura Boldrini, an associate professor of psychiatry at NewYork-Presbyterian Columbia University Medical Center. “It’s striking to me how many times we’ve seen people with these new symptoms with no previous psychiatric history.”Most veterans in the study were men, three-quarters were white and their average age was 63, so the findings may not apply to all Americans. Still, the study included over 1.3 million women and 2.1 million Black patients, and Dr. Al-Aly said “we found evidence of increased risk regardless of age, race or gender.”There are several possible reasons for the increase in mental health diagnoses, Dr. Al-Aly and outside experts said. Dr. Boldrini said she believed the symptoms were most likely influenced by both biological factors and the psychological stresses associated with having an illness.“In psychiatry, it almost always is an interplay,” she said.Research, including brain autopsies of patients who died of Covid-19, has found evidence that Covid infection can generate inflammation or tiny blood clots in the brain, and can cause small and large strokes, said Dr. Boldrini, who has conducted some of these studies. In some people, the immune response that is activated to fight against a coronavirus infection may not shut down effectively once the infection is gone, which can fuel inflammation, she said.“Inflammatory markers can disrupt the ability of the brain to function in many ways, including the ability of the brain to make serotonin, which is fundamental for mood and sleep,” Dr. Boldrini said.By themselves, such brain changes may or may not cause psychological problems. But, if someone is experiencing stress from having felt physically ill or because having Covid disrupted their lives and routines, she said, “you may be more prone to not being able to cope because your brain is not functioning 100 percent.”Dr. Harrison, who has conducted other studies with large electronic medical databases, noted that such analyses can miss more granular information about patients. He also said that some people in the comparison groups might have had Covid and not been tested to confirm it, and that some Covid patients might have been more likely to receive diagnoses because they were more worried about their health after Covid or because doctors were quicker to identify psychological symptoms.“There’s no one analysis that tells you the whole story,” Dr. Al-Aly said. “Maybe all of us or most of us experienced some sort of an emotional distress or mental health stress or some sleep problem,” he added. “But people with Covid did worse.”

If further study confirms the findings, they could lead to ways to prevent and treat the complex condition.It is one of many mysteries about long Covid: Who is more prone to developing it? Are some people more likely than others to experience physical, neurological or cognitive symptoms than can emerge, or linger for, months after their coronavirus infections have cleared?Now, a team of researchers who followed more than 200 patients for two to three months after their Covid diagnoses report that they have identified biological factors that might help predict if a person will develop long Covid.The study, published Tuesday by the journal Cell, found four factors that could be identified early in a person’s coronavirus infection that appeared to correlate with increased risk of having lasting symptoms weeks later.The researchers said they had found that there was an association between these factors and long Covid (which goes by the medical name post-acute sequelae of Covid-19, or PASC) whether the initial infection was serious or mild. They said that the findings might suggest ways to prevent or treat some cases of long Covid, including the possibility of giving people antiviral medications soon after an infection has been diagnosed.“It’s the first real solid attempt to come up with some biologic mechanisms for long Covid,” said Dr. Steven Deeks, a professor of medicine at the University of California, San Francisco, who was not involved in the study.He and other experts, along with the study authors themselves, cautioned that the findings were exploratory and would need to be verified by considerably more research.Still, Dr. Deeks said: “They’ve identified these four major factors. Each is biologically plausible, consistent with theories that other people are pursuing, and importantly, each is actionable. If these pathways get confirmed, we as clinicians can actually design interventions to make people better. That is the take-home message.”One of the four factors researchers identified is the level of coronavirus RNA in the blood early in the infection, an indicator of viral load. Another is the presence of certain autoantibodies — antibodies that mistakenly attack tissues in the body as they do in conditions like lupus and rheumatoid arthritis. A third factor is the reactivation of Epstein-Barr virus, a virus that infects most people, often when they are young, and then usually becomes dormant.The final factor is having Type 2 diabetes, although the researchers and other experts said that in studies involving larger numbers of patients, it might turn out that diabetes is only one of several medical conditions that increase the risk of long Covid.“I think this research stresses the importance of doing measurements early in the disease course to figure out how to treat patients, even if we don’t really know how we’re going to use all that information yet,” said Jim Heath, the principal investigator of the study and president of the Institute for Systems Biology, a nonprofit biomedical research organization in Seattle.“Once you can measure something, then you may be able to start doing something about it,” Dr. Heath said, adding: “We did this analysis because we know patients will go to physicians and they’ll say that they’re tired all the time or whatever, and the physician just tells them to get more sleep. That’s not very helpful. So, we wanted to actually have a way to quantify and say that there’s actually something wrong with these patients.”The complex study had several components and involved dozens of researchers at several universities and centers including the Institute for Systems Biology, the University of Washington and Swedish Medical Center in Seattle, where the study’s lead medical author, Dr. Jason Goldman, is an infectious disease specialist.The primary group of patients included 209 people, ages 18 to 89, who were infected with the coronavirus during 2020 or early 2021 and were seen at Swedish Medical Center or an affiliated clinic. Many were hospitalized for their initial infections, but some were seen only as outpatients. Researchers analyzed blood and nasal swabs when patients were diagnosed, during the acute phase of their infections and two to three months later.A tattoo of the demon Mr. Gillotte hallucinated during the Covid delirium he experienced after he was taken off the ventilator.Joshua Bright for The New York TimesThey surveyed the patients about 20 symptoms associated with long Covid, including fatigue, brain fog and shortness of breath, and corroborated those reports with electronic health records, Dr. Heath said.He said that 37 percent of the patients had reported three or more symptoms of long Covid two or three months after infection. A further 24 percent reported one or two symptoms, and 39 percent reported no symptoms. Of patients reporting three or more symptoms, 95 percent had one or more of the four biological factors identified in the study when they were diagnosed with Covid-19, Dr. Heath said.The most influential factor appeared to be autoantibodies, which were associated with two-thirds of the cases of long Covid, Dr. Heath said. Each of the other three factors showed up in about a third of the cases, he said, and there was considerable overlap, with several factors identified in some patients.The researchers corroborated some of their findings in a separate group of 100 patients, many with mild initial infections, from research led by Dr. Helen Chu at the University of Washington. The researchers also compared their results to data from 457 healthy people.“The study is large and comprehensive and is a great resource for the community studying long Covid,” said Akiko Iwasaki, an immunologist at Yale, who was not involved in the research.Dr. Avindra Nath, who is chief of the section on infections of the nervous system at the National Institute of Neurological Disorders and Stroke and was not involved in the study, called the study well designed but pointed out several weaknesses, including the fact that patients had been followed for only two to three months. “This might be too short a time frame,” he said. “Some might just improve spontaneously with time.”Dr. Iwasaki noted that 71 percent of the patients in the primary group had been hospitalized, limiting the ability to conclude that the biological factors were equally relevant for people with mild initial infections. The Coronavirus Pandemic: Key Things to KnowCard 1 of 4Omicron in retreat.