The Brief

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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Similar questions bedevil researchers pursuing another theory.

Research shows that people with long COVID have high levels of Epstein-Barr antibodies and that an acute COVID infection can trigger reactivation of the virus.

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.

Updated March 21, 2026 at 16:04 PM ET

Robert Mueller, the former FBI director and special counsel who led the high-profile investigation into Russian interference in the 2016 election and the possible obstruction of justice by President Trump, died on Friday at 81.

"With deep sadness, we are sharing the news that Bob passed away," his family said in a statement Saturday shared with NPR. No cause of death was given.

Mueller had been diagnosed with Parkinson's disease four years ago, his family told The New York Times in August.

Trump, who openly despised Mueller and his investigation, celebrated his death on Saturday.

"Good, I'm glad he's dead," the president posted on social media. "He can no longer hurt innocent people!"WilmerHale, the law firm where Mueller served as a partner, remembered Mueller as a "friend" who was "an extraordinary leader and public servant and a person of the greatest integrity."

"His service to our country, including as a decorated officer in the Marine Corps, as FBI Director, and at the Department of Justice, was exemplary and inspiring," a spokesperson for WilmerHale told NPR in a statement. "We are deeply proud that he was our partner. Our thoughts are with Bob's family and loved ones during this time."

Path to public service

Born on Aug. 7, 1944 in New York City, Mueller was raised in Philadelphia and graduated from Princeton University in 1966. He received a master's degree in international relations from New York University.

Mueller, throughout his career, ran toward tough assignments. Following the lead of a classmate at Princeton, Mueller enrolled in the Marines and served in the Vietnam war. He earned the Bronze Star for rescuing a colleague. Mueller said he felt compelled to serve during that conflict, an idea he returned to throughout his life.

Law professor and former Justice Department lawyer Rory Little knew Mueller for many years.

"Bob is kind of a straight arrow, you know, wounded in Vietnam," Little said. "You keep wanting to hunt for where is the crack in that façade — 'Where is the real Bob Mueller?' — and after a while you begin to realize that's the real Bob Mueller. He is exactly who he appears to be. This kind of sour-faced, not a lot of humor, sort of all-business guy. That's him."

But with his closest friends, Mueller let down his guard. They teased him — saying Mueller would have made an excellent drill instructor on Parris Island, where Marine recruits are trained.

Instead, Mueller went to law school at the University of Virginia. He joined the Justice Department in 1976. There, he prosecuted crimes, big and small, for U.S. attorneys in San Francisco and Boston. He was a partner at Hale and Dorr, a Boston law firm now known as WilmerHale.

He later became a senior litigator prosecuting homicides at the U.S. attorney's office in Washington, D.C.

Head of the FBI

In 2001, President George W. Bush nominated him to serve as the director of the FBI. Mueller was sworn in a week before the Sept. 11 terrorist attacks.

"I had been a prosecutor before, so I anticipated spending time on public corruption cases and narcotics cases and bank robberies, and the like. And Sept. 11th changed all of that," Mueller told NPR during an interview in 2013.

He shifted the bureau's attention to fighting terrorism. He staffed up the headquarters in Washington. He pushed those agents to try to predict crimes and to act before another tragedy hit.

"He directed and implemented what is arguably the most significant changes in the FBI's 105-year history," said his former FBI deputy, John Pistole.

Along the way, Mueller drew some criticism when his agents erred. During the investigation of the deadly anthrax attacks, the bureau focused on the wrong man as its lead suspect.

Mueller left the bureau in 2013.

Return to the national spotlight

After Trump fired FBI Director James Comey, Mueller in May 2017 was appointed by then Deputy Attorney General Rod Rosenstein as special counsel to oversee the probe into Russian meddling in the 2016 election and possible connections to Trump associates.

Trump called the investigation "a witch hunt" and Republicans in Congress started to attack the investigators.

When then the investigation eventually concluded in March 2019 with the more than 400-page "Mueller report," the special counsel said the investigation did not establish that Trump's campaign or associates colluded with the Russian government to influence the 2016 election. The report did not take a position on whether Trump obstructed justice.

Mueller said the report spoke for itself. But Democrats wanted more and insisted he testify. A reluctant witness, Mueller once again fulfilled his duty. He was visibly older than at the time of his appointment and kept his testimony restrained.

He said Justice Department guidelines would not allow him to charge a sitting president with criminal wrongdoing. But he also refused to exonerate Trump.

"If we had had confidence that the president clearly did not commit a crime, we would have said so," Mueller later told Congress.

In the end, the team charged 37 people and entities, including former campaign chair Paul Manafort, national security adviser Michael Flynn and 25 Russians.

Trump went on to grant clemency to or back away from criminal cases against many of the people Mueller's investigators had charged.

Copyright 2026 NPR

At the Koreatown Senior and Community Center, people were used to seeing Keum-soon Lee arrive early. When she didn’t show up for the 11 a.m. group harmonica class at the center last Friday, people took notice. 

“She would always be there first,” said conductor Eun-young Kim. “If she couldn’t come, she would tell me ahead of time. This time, I didn’t receive any messages from her. I thought, something isn’t right.”

Kim tried calling and sending messages. She didn’t get a response.

Members of the center later learned that Lee, 73, was critically injured in a hit-and-run crash while biking home in Koreatown after attending early morning prayer at her church. She died in a hospital March 13 from her injuries, according to the Los Angeles Police Department.

“I was shocked,” said Jin-soon Baek, who has played with Lee for years. “We’ve been friends for a long time. We ate together, practiced together. She was like a sibling to me.

“She was so hardworking. Always the first one there to sign in for class. She’d walk ahead of me and I’d follow behind. That’s how it always was.”

Baek, who is in her 80s, said the two also shared something more personal: Both had cancer.

“I had cancer years ago, and she was going through treatment recently,” Baek said. “We understood each other.”

In January, Lee played with the harmonica ensemble at an LA Kings game. Lee spoke with a journalist about undergoing surgery and chemotherapy, and what the group meant to her. 

“I think I’ve almost fully recovered,” Lee told journalist Chase Karng at the hockey game. “Even while receiving chemotherapy, I felt encouraged when I heard that I could perform here.”

At the Koreatown Senior and Community Center, people were used to seeing Keum-soon Lee arrive early. When she didn’t show up for the 11 a.m. group harmonica class at the center last Friday, people took notice.

Lee was born in 1952 in South Korea and immigrated to the United States in 1998. She was an elder at Saehan Presbyterian Church in Pico Union and is survived by her husband, Sang-rae Lee, and son, Young-jo Lee.

The senior center, where Lee was a fixture and known as a reliable friend, has designated March 20 as a day of mourning.

On Friday, Lee’s church held a funeral service, where members of the harmonica ensemble performed the hymn, “Nearer My God to Thee,” in her memory.

“I usually don’t attend funeral services, but I had to come for hers,” said Alice Kim. “Whenever I came to church, I would see her watering the grass, bent over, and she would smile and say, ‘You’re here, Alice,’ and hand me the Sunday bulletin.”

In her eulogy, elder Gyu-sook Lee said the sudden loss has hit the congregation hard.

“She always greeted everyone with a warm smile,” she said. “She was the kind of person who always stepped forward first to do the hard work that no one else wanted to do. And when she took something on, she saw it through to the end.”

At the Koreatown Senior and Community Center, people were used to seeing Keum-soon Lee arrive early. When she didn’t show up for the 11 a.m. group harmonica class at the center last Friday, people took notice.

“She still had so many years ahead of her,” Baek said. “She was younger than us. Full of hope. It feels like it should have been me instead.”

According to police, Lee was riding through a crosswalk when a white Dodge Ram truck turning right struck her around 6:40 a.m. near Olympic Boulevard and Vermont Avenue. The driver briefly stopped, then drove away, authorities said.

Investigators found the truck and are looking into whether the driver was impaired on drugs or alcohol. The truck was seized and there was no information about the driver.

Kim, the conductor, said Lee was the first person to reach out to her when she started to lead the ensemble in September. 

“She sent me a message saying thank you for coming,” Kim said. “She was such a special person to me.” 

At Friday’s service, speaker after speaker described Lee as someone who was a light in every community she was part of. 

“The way she served the church behind the scenes became a lesson in faith for all of us. There isn’t a single part of this church that hasn’t felt her touch. Her warmth, her love, her dedication — I can still feel it,” Gyu-sook Lee said.

When Gilbert Lindsay became the first Black person elected to Los Angeles City Council in 1963, it gave the residents of the predominantly Black District 9 someone who understood the challenges they faced living in South Central. 

This area was the center of Black political power in LA because it was one of the few places in the city Black people were allowed to live and thrive due, in part, to housing restrictions. For the next 63 years, voters in this district — which includes historic South Central, Exposition Park and a small portion of downtown Los Angeles — consecutively chose a Black representative. 

That will end with Curren D. Price Jr., the current District 9 councilmember who can’t run again due to term limits. 

Twelve candidates announced campaigns in February to replace Price. Of them, six candidates have qualified to be on the June 2 primary election ballot, none of whom are Black. They include: Estuardo Mazariegos, Elmer Roldan, Jorge Hernandez Rosas, Jorge Nuño, Martha Sánchez and Jose Ugarte. 

The list is a reflection of the demographic shift of the area, but candidates also told The LA Local that it shows the strength of the district’s Black-Latino political coalition. And with the civil rights gains since the 1960s, while some locals are concerned that issues facing Black voters won’t get the attention they need, others who live in the district said they’re less concerned with what their representative looks like. Instead, they said they want someone who listens and gets things done. 

“As long as you do good in the community, we’re going to be happy,” said Dennis Anya, who works on Central Avenue and has lived in the district for nearly 40 years.

What the demographic shifts in District 9 mean for the June election

The upcoming election comes as the demographics have changed in District 9 and South LA. The Black population in South Los Angeles was 81% in 1965, according to a special census survey from November 1965 of South and East LA. 

As of 2021, District 9, specifically, is about 78% Latino and 13% Black, according to LA City Council population demographic data taken that year as part of a redistricting effort. 

Officials have predicted the district’s shift for years. Former City Councilmembers Kevin De León and Nury Martinez discussed the district’s future in the leaked 2021 audio — checkered with racist remarks — that the LA Times reported in 2022.“This will be [Price’s] last four years,” De Leon said at one point in the conversation, the transcript of which the LA Times published in full. “That eventually becomes a Latino seat.” 

Erin Aubry Kaplan, a writer and columnist who traces her family’s roots to South Central, told The LA Local that because District 9 has historically voted for a Black candidate, there is some anxiety amongst Black voters about losing Black representation in Los Angeles. 

“I would hope that whoever wins, will carry the interest of Black folk forward,” she said.

Manuel Pastor, a USC professor and co-author of “South Central Dreams: Finding Home and Community in South LA,” told The LA Local that traditionally, voters are older. While District 9 is now home to a younger, immigrant community, they may not vote at the same rate as older generations, and undocumented residents are ineligible to vote.  

Pastor said it’s likely for this reason that the current District 9 candidates are not emphasizing being Latino but are modeling their campaigns after other city leaders and focusing on Black-Latino solidarity. 

“Just because the demographics have changed, doesn’t mean that the voting population has changed,” Pastor said.  

Here’s what the candidates say about the transformation of District 9

Chris Martin, one of the two Black candidates who campaigned for the seat but did not qualify for the ballot, said he believes the city’s Black elected officials should have supported Black candidates in the race. Martin said he will challenge the city clerk’s decision on his nomination petition in court. 

“The story of Black political power in the city of Los Angeles is dying,” Martin said. “I felt like I had a good chance of keeping it alive.” 

When Gilbert Lindsay became the first Black person elected to Los Angeles City Council in 1963, it gave the residents of the predominantly Black District 9 someone who understood the challenges they faced living in South Central.

Michelle Washington, the other Black candidate who also did not qualify, did not respond to a request for comment.Price, the current District 9 councilmember, endorsed his deputy Jose Ugarte in the race and wrote in a statement that this election is about solidarity. 

“As a Black man who has served a majority-Latino district, I know that progress in South Central has always come from Black and Brown families moving forward together,” Price wrote. “We’ve had to fight harder for housing, safety, opportunity and the basic investments every neighborhood deserves. And when we’ve made gains, it’s because we stood united.”  

Five of the six candidates who qualified for the ballot told The LA Local that not having a Black candidate on the ballot doesn’t diminish the place of the district’s Black community. (Candidate Jorge Hernandez Rosas did not return requests for comment.) 

“It has always been a Black community and will always be a Black community. This isn’t about a passing of the baton or one community taking over another. It’s about building a solidarity movement,” Estuardo Mazariegos said. 

Elmer Roldan, who carries endorsements from LA Mayor Karen Bass and City Council President Marqueece Harris-Dawson, said the district needs a councilmember who won’t leave anyone behind.“We have to avoid at all costs contributing to Black erasure and Black displacement,” Roldan said.

Ugarte said that the major quality of life problems — like dirty streets and broken street lights — affecting the neighborhood’s Black and brown communities haven’t changed since he was a child living in the district. 

“The same issues are still here,” he said. 

Here’s what happens next

If you haven’t registered to vote and you want to receive a vote-by-mail ballot, you must register to vote by May 18.

Results from the primary election will be certified by July 2. If no candidate receives more than 50% of the vote, the top two candidates will move on to the general election on Nov. 3, according to the City Clerk’s website. 

The winner of District 9 will begin a four-year term Dec. 14.

The L.A. County Medical Examiner has released the cause of death for Emily Beutner, the daughter of former LAUSD Superintendent Austin Beutner.

The 22-year-old died from the effects of a combination of drugs, including two linked to the opioid known as kratom — mitragynine and 7-hydroxymitragynine — according to the statement released by the medical examiner Friday.

A county health official told our partner CBS L.A. that kratom products are sometimes sold as natural remedies but are illegal and unsafe.

The other two substances cited as causes of death were quetiapine and mirtazapine — the former is an antipsychotic medication, and the latter is used to treat depression, according to the Mayo Clinic.

The former Loyola Marymount University student was found alone and suffering from medical distress by L.A. County Fire Department personnel shortly after midnight in a field by a highway in Palmdale on Jan. 6. She was transported to a hospital and pronounced dead soon after.

After his daughter's death, Beutner dropped out of the L.A. mayoral race.

The Medical Examiner said the manner of death was ruled a suicide.

Resources

If You Need Immediate Help

• If you or someone you know is in crisis and need immediate help, call the Suicide Prevention Lifeline at 988 or go here for online chat.

If you or someone you know is experiencing a crisis, you can dial the mental health lifeline at 988.

Additional resources