Researchers looking for root causes of long COVID work in the autopsy suite inside the Clinical Center at the National Institute of Health in Bethesda, Maryland.
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Valerie Plesch
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Bloomberg via Getty Images
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There's still no validated treatment or diagnostic test specifically for long COVID's often disabling symptoms — although there are many candidates.
Why it matters: Clinicians who treat long COVID are acutely aware of the unsettled nature of the field. "You do sort of feel like you're out in the wilderness," says Dr. Rasika Karnik, medical director of UChicago Medicine's post-COVID clinic.
What we do know: If long COVID were a crime scene, authorities would have no shortage of leads. They've pinpointed a handful of possible reasons why patients suffer from an array of chronic symptoms. The tricky thing is disentangling which mechanisms are bystanders and which are actually doing the damage.
For people suffering from long COVID's often disabling symptoms, including intense fatigue, breathing troubles, cognitive issues and heart palpitations, the list of scientific unknowns may sound defeating. There's still no validated treatment or diagnostic test specifically for the condition, although there are many candidates.
Clinicians who treat long COVID are acutely aware of the unsettled nature of the field. "You do sort of feel like you're out in the wilderness," says Dr. Rasika Karnik, medical director of UChicago Medicine's post-COVID clinic.
Karnik first began seeing long COVID patients in the fall of 2020. There's more information to work with now, she says, but doctors' approach still comes down to treating individual symptoms, rather than the underlying cause of the illness. "It's hard to look a patient in the eyes and say 'we're not quite sure yet' and to keep repeating that," she says.
But researchers are making progress in the field, and they presented their recent findings at one of the first major gatherings dedicated to sharing emerging evidence about the possible root cause of long COVID and implications for treatment.
"I know there's been a lot of frustration that there haven't been faster answers," says Dr. Catherine Blish, a professor of medicine at Stanford University and one of the organizers of the conference, held by the nonprofit Keystone Symposia in Santa Fe, N.M., in late August.
"But in all honesty, we are so much further ahead at this relative point than for any other major disease in my lifetime as an infectious disease specialist," she says.
The meeting underscored that scientists have made headway in developing evidence of a clear biological basis for what patients have been reporting for years.
"I've never doubted it — people are suffering," says Harlan Krumholz, a cardiologist at Yale University who's involved in long COVID research. "But we're now seeing imaging evidence, biopsy evidence, physiologic testing evidence of derangements in people who have long COVID."
Here are some of the new findings and promising lines of research highlighted during the three-day gathering.
Narrowing in on some key suspects behind the disease
If long COVID were a crime scene, authorities would have no shortage of leads.
They've pinpointed a handful of possible reasons why patients suffer from an array of chronic symptoms. The tricky thing is disentangling which mechanisms are bystanders and which are actually doing the damage.
"At this point, we have hints and correlative data," says Blish. "We can say we see this finding in a subset of people, but that doesn't mean it's the cause of their problems."
Take the theory of viral persistence: There's now strong evidence that protein and genetic material from SARS-CoV-2 persist in the blood and tissue of some long COVID patients well after their initial illness. Scientists believe these "viral reservoirs" could be driving many of the problems in long COVID patients, although it isn't yet clear exactly how this is happening — and whether the virus itself is replicating.
Dr. Michael Peluso, an infectious disease specialist at the University of California, San Francisco, told conference attendees that his team is now confident in their data showing pieces of viral antigen in the blood of people anywhere from six months to more than a year after they've had COVID-19.
They compared these blood samples to ones collected years before the pandemic to verify their conclusions. "That's a very, very important finding, showing that this is indeed real," he says.
But the story gets more messy from there because these viral reservoirs may not be the primary culprit.
While they are more likely to find viral persistence in the most symptomatic long COVID patients, not everyone with long COVID has it, Peluso notes, "And then really importantly, we're also seeing this in some people who feel totally fine — and we don't know what that means."
Finding activated T cells where they shouldn't be
Other leads have come from imaging technology that traces the activity of T cells, a type of white blood cell, which are part of the body's main antiviral immune response.
"We saw some very unexpected findings," says Dr. Timothy Henrich, an associate professor of medicine at the University of California, San Francisco.
His lab has found activated T cells in the gut wall, lung tissue, certain lymph nodes, the bone marrow, the spinal cord and the brainstem, long after someone's initial infection.
"You really shouldn't have activated T cells in the spinal cord or the brainstem," he says. "We are seeing evidence of this immune response in areas we don't typically see in the setting of an acute viral infection."
Here too the immunological detective work opens up even more questions: This T cell activity is also present in people who've recovered from an infection and have no long COVID symptoms, although Henrich notes the levels appear to be higher in certain tissues of people with long COVID.
So what does this immune response actually indicate about the underlying cause of the disease?
Henrich says T cell activity could be evidence that the immune system is trying to purge the viral reservoirs, or that the immune response has gone awry, possibly in the form of an autoimmune response, and is "doing damage to people, even if the virus has been cleared or is not replicating in those tissues," he says.
Patients and advocates for people suffering from long COVID and myalgic encephalomyelitis/chronic fatigue syndrome hosted an installation of 300 cots in front of the Washington Monument on the National Mall in Washington, D.C., in May, to represent the millions of people suffering from post-infectious disease.
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Andrew Harnik
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Similar questions bedevil researchers pursuing another theory.
Akiko Iwasaki, a professor of immunobiology at Yale University, says it's well known that this herpesvirus can lead to a "long COVID-like syndrome," but whether or not the reactivation is driving long COVID symptoms — or just an indication of a dysregulated immune system — remains to be seen.
All of those involved in research stress that they don't expect just one answer to long COVID. It's likely that many of these theories about its underlying cause are interrelated. And certain mechanisms may only be causing symptoms in some patients and not others.
Microclots could point the way to treatment
Early in the pandemic, it was recognized that COVID-19 can wreak havoc on the vascular system, in particular causing inflammation and damage to the inner lining of blood vessels, known as endothelial cells.
Resia Pretorius, a medical researcher at Stellenbosch University in South Africa, says the clotting and hyperactivation of platelets in long COVID is essentially a "persistent continuation" of what happens during an acute infection within the blood vessels.
Her research has focused on the role of tiny, harmful blood clots she's seeing in the blood of long COVID patients that appear to have "trapped inflammatory molecules that you might expect inside the blood if you have inflamed [or] damaged endothelial layers."
"It's not unique to long COVID, but long COVID has so much more of these inflammatory molecules in circulation," says Pretorius. "And what makes it so interesting is that the spike protein drives these microclots to form."
As the clots accumulate, they may choke off blood flow, preventing oxygen from reaching tissue.
In Santa Fe, Pretorius shared preliminary data from her team showing that so-called "triple therapy" — a combination of three medications — targeting clotting and platelet hyperactivation could benefit some long COVID patients. The preprint showed that this regime resolved symptoms in the majority of the 91 patients who were followed, although the results are not yet peer-reviewed and the study was not a clinical trial.
The approach is not without risk; many patients reported bruising, some had nosebleeds and one reported a gastrointestinal bleed.
Pretorius says microclots are not necessarily the root cause of long COVID, though.
It could be that viral reservoirs are actually helping trigger this vascular mayhem in the first place. These microclots, if left untreated, could also tie into other problems seen in long COVID patients, perhaps leading some to develop autoimmunity, says Pretorius. "That is a problem to solve because we know autoimmune diseases are notorious for being so, so difficult to treat."
Sex differences may play a role in long COVID risk
In general, males tend to do worse during an acute bout of COVID-19, but studies show that long COVID appears to be more prevalent among females. Yale's Iwasaki says this is also the case for other "post-acute infection syndromes."
This background led Iwasaki's lab to look into sex differences in the immune profiles of long COVID patients, in hopes of finding another path to understanding what could be driving the illness. She says they've found that reactivation of Epstein-Barr virus and the activation of T cells are more prevalent among females, whereas males have different "immune signatures."
"We're already starting to see sex differences in long COVID symptoms, as well as potentially the autoimmunity more associated with female patients," she says. "This insight is critical going forward because now we can separate out long COVID into different clusters. And depending on the driver of the disease, we can start targeting it with proper medicine."
Iwasaki's lab has also zeroed in on the role of hormones.
At the conference, she shared evidence of reduced cortisol levels in long COVID patients and shared a separate, unpublished finding that female long COVID patients tend to have reduced testosterone levels and that males have reduced estradiol levels.
Those who had lower testosterone (compared to the controls who don't have long COVID symptoms) also have higher activation of T cells, whether they're males or females, says Julio Silva, a graduate student in Iwasaki's lab who presented the new findings on testosterone. And this was "associated with higher neurological symptoms and overall higher symptom burden," says Silva.
The impetus to look at testosterone was, in part, because of "anecdotes from trans individuals who were informing us that while on testosterone therapy, their symptoms had improved dramatically," says Silva. While the results are preliminary and need to be replicated, he says they at least raise the question "could hormonal therapy help?"
Taken together, Iwasaki says their data strongly suggest there could be problems in the area of the brain that's responsible for regulating these hormones.
Viral persistence offers one possible target for treating long COVID
In the absence of a clear roadmap for treating long COVID, doctors and patients have taken to trying all kinds of therapies — from antivirals to drugs approved for treating addiction.
"All of this research is so critical to understanding the underlying mechanisms of long COVID," says Lisa McCorkell, co-founder of the advocacy group Patient-Led Research Collaborative. "We need to pair that with focusing on clinical trials. We have enough evidence right now to at least try some things."
In Santa Fe, UCSF's Peluso outlined how his team had just launched a small trial using monoclonal antibodies to target the coronavirus spike protein in long COVID patients — one vehicle for testing whether viral persistence is the underlying cause of at least some patients' symptoms. Meanwhile, Iwasaki and Krumholz, both at Yale, have started a clinical trial testing whether a 15-day course of Paxlovid can help alleviate symptoms.
Stanford's Blish points out that as more clinical trials start up, their success will hinge on being deliberate about which patients should be enrolled, since long COVID is a catch-all term for what may be multiple different illnesses.
"We need to understand in detail who's most likely to benefit from those trials, because if we just take everyone, that trial will fail," she says.
Many other trials are in the works, too, but Dr. Jennifer Curtin says those will inevitably take time to produce evidence that trickles down to patient care.
"It's that tough sort of in-between status right now," says Curtin, co-founder of the telehealth clinic RTHM that treats long COVID and other overlapping conditions like myalgic encephalomyelitis/chronic fatigue syndrome, or ME/CFS for short. "So what do you do for the people who are sick and suffering now until we get that data?"
Curtin, who has lived with ME/CFS herself, says their clinic's approach is to perform intensive workups, draw lots of blood and try to identify which symptoms they can treat.
"Treatment is very much individually tailored," she says. "Right now it's a journey that you take with your patients. You're going through this together. You're both learning on this road and it can be tough."
Always in the backdrop at the Santa Fe gathering was the question of whether there would be enough funding — be it from the U.S. Congress or the pharmaceutical industry — to advance the research agenda toward treatments.
"What we really need here is industry engagement. We need funding for clinical trials. And that, to me, is something that's missing," says McCorkell.
News that Warner Bros. Discovery is up for sale has Hollywood buzzing.
Where things stand: The legendary film studio, which has grown to include streaming services and cable channels, is currently accepting non-binding bids until Thursday. According to company spokesperson Robert Gibbs, they expect to have a decision about the sale by Christmas.
Why it matters: Earlier mergers, like Disney's 2019 acquisition of Fox, cut the number of films studios released theatrically — a troubling trend for theater owners already coping with consolidation and streaming.
News that Warner Bros. Discovery is up for sale has Hollywood buzzing.The legendary film studio, which has grown to include streaming services and cable channels, is currently accepting non-binding bids until Thursday. According to company spokesperson Robert Gibbs, they expect to have a decision about the sale by Christmas.
It's become something of a Hollywood parlor game to guess who will ultimately take overthe business, which was founded in 1923 by four brothers: Harry, Albert, Sam and Jack Warner. They owned a movie theater in Pennsylvania before coming to Hollywood to make movies.
Warner Brothers Pictures found one of its first silent picture stars in a German shepherd named Rin Tin Tin. By 1927, the studio made history with its feature-length "talkie" picture: The Jazz Singer, starring Al Jolson.
Over the years, Warner Brothers has made or distributed countless iconic films including: Casablanca, The Big Sleep and The Maltese Falcon in the 1940's. The list goes on, with titles like A Clockwork Orange, Goodfellas, Barbie, as well as Bugs Bunny and all the Looney Tunes cartoons.
Warners Brothers has had multiple owners over the decades. Three years ago, Warner Media, as it was called, merged with Discovery. And in June, the company announced it would split in two, with film, TV and streaming studios in one camp, and in the other, mostly legacy cable channels, including CNN.
The planned split has not yet happened, and a new buyer might get the entirety of Warner Bros. Discovery and its film and TV libraries.
As the film industry continues to consolidate, there's speculation that Warner Brothers' old rival Paramount could take over. Having just merged as Paramount Skydance, CEO David Ellison has already made several overtures.
The idea of streaming giant Netflix buying the company has raised antitrust concerns on Capitol Hill. In an earnings call last month, Netflix co-CEO Ted Sarandos told investors, "We've been very clear in the past that we have no interest in owning legacy media networks. There is no change there."
Industry watchers suggest other suitors could be Comcast, Amazon, or an investor who's not already in the entertainment business.
Regardless of whoever does end up buying the company, theater owners say they hope making movies for cinemas will be a priority.
"As long as we have more movies," says Daniel Loria, senior vice president at The Boxoffice Company, which analyzes data from studios and theaters. "That doesn't mean the same amount, doesn't mean less, but more movies. I think you're going to find folks in the movie theater industry support any business decision that gets us there."
Loria recalls that after Disney purchased Fox and Fox Searchlight, their combined studios significantly reduced the number of films they released in the theaters. Crunching the numbers, Loria says in 2016, a year before the merger announcement, Disney and Fox released a total of 38 theatrical films. This year, the consolidated studios released 18.
That's a problem for theater owners who've been struggling to bring audiences back to cinemas after the COVID-19 pandemic shut them down; they're competing with movie-watching on TVs, computers and phones.
Some theater owners and cinephiles also fear studio conglomerates will only greenlight a few big-budget blockbusters, leaving the lower budget indies behind.
"The concern is you're going to see less of that risk taking, less of that experimentation and less of that embracing new directors, new filmmakers in the future," says Max Friend, the CEO of Filmbot, the ticketing platform for independent cinemas in the U.S. "It's really important that there are studios that are funding and supporting, cultivating that kind of work."
He points out that this year, Warner Brothers made a string of critical hits, including Ryan Coogler's Sinners, the horror film Weapons and Paul Thomas Anderson's One Battle After Another.
Friend wonders if the next owner will take similar risks with future original, creative films.
Warner Bros. Discovery is a financial supporter of NPR.
Matt Dangelantonio
directs production of LAist's daily newscasts, shaping the radio stories that connect you to SoCal.
Published November 19, 2025 5:23 PM
Los Angeles County District Attorney Nathan Hochman is looking into fake claims of childhood sexual abuse filed against the county as part of two large settlements it approved earlier this year.
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Robert Gauthier
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Topline:
Los Angeles County District Attorney Nathan Hochman says his office is looking into allegations that people filed fake claims of childhood sexual abuse as part of two large settlements the L.A. County Board of Supervisors approved this year.
Potential amnesty: Hochman said anyone who filed a fraudulent claim and comes forward to cooperate with his office could potentially avoid prosecution. He said his office would offer something called "use immunity," which he said means someone who comes forward and shares complete, truthful information about a fraudulent claim they filed would, in exchange, not have those words used against them in court. He would not go as far as to say that doing so would protect them from prosecution.
" It's not a guarantee, but it is certainly a significant factor in deciding of the probably what will amount to hundreds of cases, potential cases that we might have, which ones we go forward on and which ones we don't."
The backstory: In April, L.A. County supervisors approved a $4 billion settlement for thousands of people who said they were sexually abused as children while under the county's supervision. The settlement stems from a lawsuit filed in 2021 and grew to include claims against several county departments, including Probation, Children and Family Services, Parks and Recreation, Health Services, Sheriff and Fire. In late October, the Board signed off on a second payout of $828 million for a separate batch of claims.
Why it matters: Hochman said it will ultimately be taxpayers footing the bill for those two sums, and he wants to make sure L.A. County taxpayers aren't on the hook for fake claims.
" That'll be you and me paying for that," Hochman said. "That'll be our children paying for it. ... These are valuable dollars that otherwise could go to other purposes."
Why now: The D.A.'s announcement follows a unanimous vote by L.A. County supervisors last month to direct the county counsel to investigate fraudulent claims. Days before the vote, the L.A. Times reported some plaintiffs were paid cash in exchange for agreeing to work with a law firm to sue the county.
What's next: The D.A.'s office says anyone with information about false sex abuse claims can call the hotline for the investigation at (844) 901-0001, or report it online.
Makenna Sievertson
has been covering the case and attending federal hearings in downtown L.A. since at least March 2024.
Published November 19, 2025 3:34 PM
A view of City Hall and its reflection from the First Street U.S. Courthouse.
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Jay L. Clendenin
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Getty Images
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A downtown hearing kicked off Wednesday, during which a federal judge will consider holding the city of Los Angeles in contempt of court. The hearing is the latest step in a long-running legal saga regarding the city's response to the region’s homelessness crisis.
Why it matters: The hearing was ordered by U.S. District Judge David O. Carter, who has been overseeing a settlement in a lawsuit brought against the city by the L.A. Alliance for Human Rights, a group of downtown business and property owners. L.A. Alliance sued the city, and county, in 2020 for failing to adequately address homelessness.
Why now: Carter said in court documents that he’s concerned the city has demonstrated a "continuous pattern of delay” in meeting its obligations under court orders. During a hearing last week, the judge pointed to several delays, including recently reported issues related to data and interviewing city employees.
Attorneys for the city have pushed back against the hearing, filing objections with the judge and making an unsuccessful emergency request with the 9th Circuit Court of Appeals to block it from happening.
What's next: The hearing will resume Dec. 2, when more witnesses can appear in person.
Read on ... for details on the hearing and who is expected to testify.
A downtown hearing kicked off Wednesday, during which a federal judge will consider holding the city of Los Angeles in contempt of court. The hearing is the latest step in a long-running legal saga regarding the city's response to the region’s homelessness crisis.
The hearing was ordered by U.S. District Judge David O. Carter, who has been overseeing a settlement in a lawsuit brought against the city by the L.A. Alliance for Human Rights, a group of downtown business and property owners. L.A. Alliance sued the city, and county, in 2020 for failing to adequately address homelessness.
Several witnesses are expected to testify during the contempt-of-court hearing, including Gita O’Neill, the new head of the region’s top homeless services agency, and Matt Szabo, the L.A. city administrative officer.
L.A. County Supervisor Kathryn Barger watched at least part of Wednesday’s hearing in the courtroom.
Why now?
Carter said in court documents that he’s concerned “the city has demonstrated a continuous pattern of delay” in meeting its obligations under court orders. During a hearing last week, the judge pointed to several delays, including recently reported issues related to data and interviewing city employees.
The judge noted that similar concerns have come up at previous hearings. Carter told attorneys for the city in March 2024 that he “indicated to the mayor that I’ve already reached the decision that the plaintiffs were misled” and “this is bad faith,” according to court transcripts.
The judge said in a Nov. 14 order that he’s concerned the “delay continues to this day.”
The contempt hearing is expected to cover whether the city has complied with court orders and provided regular updates to the court under the settlement agreement.
Reducing delays
Attorneys for the city have pushed back against the hearing, filing objections with the judge and making an unsuccessful emergency request with the 9th Circuit Court of Appeals to block it from happening.
City authorities also asked the appeals court to press pause on the judge’s order to appoint a monitor in the case to make sure the city stays on track with the settlement. The city argued that Carter handed the monitor “a blank check to interfere with the democratic process,” according to court documents.
In light of that response, attorneys for the city have argued that looking at the city’s cooperation with Garrie “would be inappropriate” during the hearing and that L.A. “cannot be held in contempt for either the substance or the manner of its compliance with the order,” according to court documents.
Previous hearings related to the settlement have elicited tense questioning of witnesses and harsh words from the judge, who has been vocal about reducing delays and moving the case forward.
In an opening statement Wednesday, Theane Evangelis — one of the attorneys representing the city — urged the judge to “turn down the heat” on the closely watched case. Evangelis said the “city is constantly under fire” in court while L.A. has made “enormous strides” in getting people off the streets.
Elizabeth Mitchell, lead attorney for L.A. Alliance, said the city treats transparency as a burden.
She said Wednesday that the “city still fights oversight harder than it fights homelessness” and that the court should address L.A. 's “consistent” delays throughout the case.
What’s next?
The hearing will resume Dec. 2, when more witnesses can appear in person.
City authorities told the court they believed a one-day hearing wouldn't be enough time to go over all the evidence.
If the judge does find the city of L.A. in contempt of court and that it "isn't doing what it promised to do," the consequences could range from nothing all the way up to serious sanctions, according to Matthew Umhofer, an attorney for L.A. Alliance.
Umhofer told LAist after the hearing that sanctions could include the court ordering more intensive monitoring of the city’s performance, imposing new requirements on the city, monetary penalties or possibly a receivership.
Carter previously stopped short of seizing control of the city’s hundreds of millions of dollars in homelessness spending and handing it to a court-appointed receiver, deciding against that option in a June ruling.
L.A. Alliance is considering asking for an extension to the settlement agreement, Umhofer said.
“The city has gotten away with not complying for a very long time,” he said. “So extending the agreement can be among the things that we might ask for ... given the pattern of delay and obstruction."
Evangelis and Bradley Hamburger, another attorney representing the city, declined LAist’s request for comment after the hearing.
Matt Dangelantonio
directs production of LAist's daily newscasts, shaping the radio stories that connect you to SoCal.
Published November 19, 2025 3:33 PM
The coastline at Nicholas Canyon Beach in Malibu.
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Courtesy of Los Angeles County Department of Beaches and Harbors
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Topline:
The Los Angeles County Public Health Department has issued an ocean water quality advisory for all L.A. County beaches after the recent record-setting, multi-day rainstorm.
Why it matters: The concern is that hazards like trash, chemicals, debris and other things from city streets and mountain areas that could make you sick may have run off during the rain into storm drains, creeks and rivers that discharge into the ocean.
What's next: The advisory is currently set to expire at 8 a.m. Saturday, but L.A. County Public Health says it could be extended if there's more rain.