Los Angeles Times

Study provides clues on long COVID

About 1 in 4 infected people have lingering symptoms. Obesity may heighten risk.

- By Corinne Purtill

From the start of the pandemic, patients and doctors alike have been frustrated by the sizable minority of coronaviru­s infections that turn into long COVID, a perplexing collection of lingering and often disabling symptoms that persist weeks, months or years after the initial infection subsides.

The condition has been reported in both children and adults; in those who had preexistin­g conditions and those in robust health; in patients hospitaliz­ed with COVID-19 and those who experience­d only mild symptoms during their initial infection.

A new study from researcher­s at USC offers some insights into the prevalence of long COVID and suggests some early clues for who might be more likely to develop long-term symptoms.

The study, published this month in Scientific Reports, found that 23% of people who had coronaviru­s infections between March 2020 and March 2021 were still reporting symptoms up to 12 weeks later.

Researcher­s recruited roughly 8,000 people, some infected and some not, to an

swer biweekly questions about their overall health and COVID-19 status. By the end of the yearlong survey period, they had a sample of 308 people who had gotten the disease at some point in the year.

After filtering out respondent­s with symptoms such as headache and fatigue prior to infection as a result of unrelated conditions like seasonal allergies, the team found that nearly 1 in 4 COVID-19 sufferers were still grappling with symptoms 12 weeks after becoming infected.

“These people are not able to do necessaril­y all the activities they would want to do, not able to fully work and take care of their families,” said Eileen Crimmins, a demographe­r at USC’s Leonard Davis School of Gerontolog­y and a coauthor of the study.

“That’s an aspect of this disease that needs to be recognized, because it’s not really as benign as some people think,” she said. “Even people who have relatively few symptoms to start with can end up with long COVID.”

Determinin­g who is at greater risk for long COVID has proved a challenge to demographe­rs and healthcare providers.

Several previous studies have identified women as being at greater risk. But the USC study found no relationsh­ip in its sample between long COVID and age, gender, race or preexistin­g health conditions including cancer, diabetes, hypertensi­on and heart disease.

It did note a higher risk in patients who had obesity prior to infection. And it also spotted some associatio­ns between specific symptoms people experience­d during their initial infection and the likelihood of developing long COVID. Patients who reported sore throats, headaches and, intriguing­ly, hair loss after testing positive were more likely to have lingering symptoms months later.

“Our assumption is that that hair loss reflects extreme stress, potentiall­y a reaction to a high fever or medication­s,” Crimmins said. “So it’s probably some indication of how severe the illness was.”

Because it covered only the first year of the pandemic, the study doesn’t account for two major developmen­ts: vaccines and variants. None of the COVID-19 patients in the sample were eligible for vaccines during the study period, and all were infected before the Alpha variant from the U.K reached U.S. shores.

Although the study’s 308 respondent­s were representa­tive of the population, no snapshot of a few hundred people can tell the whole story of the 90 million people in the U.S. who have had the virus, according to estimates from the Centers for Disease Control and Prevention.

“The authors made a commendabl­e effort to identify factors associated with long COVID,” said Dr. Alain Lekoubou Looti, a neurologis­t at Penn State University who was not involved with the study. “However, these factors may need to be confirmed in larger samples.”

The most common long COVID symptoms reported were headache, nasal congestion, abdominal pain, fatigue and diarrhea. But the study did not address many of the symptoms people living with long COVID describe as the most debilitati­ng, said Hannah Davis, a cofounder of the Patient-Led Research Collaborat­ive, a research group that focuses on the condition.

“We need work like this, but this work also indicates they aren’t very familiar with what long COVID is,” Davis said. “The list of symptoms are predominan­tly acute COVID symptoms and don’t include the most common symptoms of post-exertional malaise, cognitive dysfunctio­n, memory loss, sensorimot­or symptoms and others.”

Defining long COVID presents a challenge to those attempting to track or treat it. COVID-19 is a chimerical beast — symptoms evolve as the condition drags on, and can vary widely among patients.

The fluidity of long COVID makes it hard to gauge its prevalence. Various studies have placed the percentage of people reporting enduring symptoms 12 weeks after their initial infection at anywhere from 3% to 50%.

“We need a universal case definition before we can really understand the prevalence of long COVID. Right now, the definition varies wildly across studies, leading to a big range in prevalence estimates,” said Jana Hirschtick, an epidemiolo­gist with the University of Michigan’s School of Public Health. “After all this time, we still don’t have a clear picture of who is at greatest risk.”

The absence of strict diagnostic criteria is also a major issue for patients attempting to seek treatment. At the moment, long COVID is considered an “exclusiona­ry diagnosis,” meaning one that is given only after all other valid possibilit­ies have been ruled out, said Melissa Pinto, an associate professor of nursing at UC Irvine who studies the condition. In the U.S., that can mean a long and expensive process of submitting to various tests and specialist­s.

For many long COVID patients, 12 weeks is just the beginning of a months- or years-long ordeal.

“I’ve known people that have had this now for 2½ years,” Pinto said. “There’s no safety net, really, for these individual­s.”

 ?? Gary Coronado Los Angeles Times ?? VISITORS relax at the expanded Wild Rivers water park in Irvine, which reopened earlier this month.
Gary Coronado Los Angeles Times VISITORS relax at the expanded Wild Rivers water park in Irvine, which reopened earlier this month.
 ?? JEAN-FRANCOIS BADIAS Associated Press ?? MEDICAL WORKERS treat a COVID-19 patient in France in 2020. A study offers some answers on long COVID but highlights the difficulty in defining it.
JEAN-FRANCOIS BADIAS Associated Press MEDICAL WORKERS treat a COVID-19 patient in France in 2020. A study offers some answers on long COVID but highlights the difficulty in defining it.

Newspapers in English

Newspapers from United States