Long COVID continues to offer more questions than answers 27 months into the coronavirus pandemic, though researchers are slowly gaining a better understanding.
Long-term effects from SARS-CoV-2 infection, known more commonly as long COVID, has been the topic of more than 1,650 papers published in the National Library of Medicine since 2020.
When asked about long COVID, most physicians will offer up their experience and/or research with a caveat — more research is needed to know for sure.
“We’re really just starting to work this whole thing out,” said Dr. Matthew Sims, director of infectious disease research at Beaumont Health. “It’s complicated, it’s confusing. To be honest, I think we’re going to find that long COVID is the same sort of problem we see with other things and all the research that’ll end up being done on long COVID, because it’s such a big issue, may help other diseases like fibromyalgia or chronic fatigue syndrome, that are really hard to figure out right now. We don’t know.”
Researchers have made some progress however. Below are some common questions and answers related to long COVID.
What is long COVID?
The typical definition of long COVID is long-term symptoms from SARS-CoV-2 that might be experienced weeks, months or even years after primary infection.
As for specific symptoms that linger, those vary.
A recent survey conducted by the Center for Health and Research Transformation (CHRT) at the University of Michigan found breathing issues were the most common ongoing symptom, followed by loss or distorted sense of smell or taste, and lingering anxiety, depression, or other mental health issues.
Other common symptoms were nervous system symptoms, neurologic problems, diabetes, heart problems, kidney damage, and fatigue.
The Cover Michigan Survey is a public opinion telephone and online survey that includes a random sample of Michigan adults. Its results were analyzed by CHRT staff, who said many of their findings were supported by national data and additional research.
“I like to think this is sort of the tip of the iceberg with long COVID, because everything about this virus and this pandemic and this disease is so new and every day we’re still learning more stuff,” said Melissa Riba, director of research and evaluation at CHRT.
In July 2021, long COVID became a disability under the Americans with Disabilities Act. An individualized assessment is necessary to determine whether a person’s long COVID condition substantially limits them.
How common is it?
The Cover Michigan Survey found more than one in three Michiganders who reported a COVID-19 diagnosis identified themselves as a COVID long hauler. While the sample size was limited — 138 individuals with COVID, of which 48 reported long COVID — it matched or followed trends found in other studies.
Stretching globally, the University of Michigan School of Public Health analyzed 50 studies and more than 1.6 million people and found the prevalence of long COVID to be around 43%.
“With the overall rates, if you look at most of the literature, it generally falls among the range of between 25% and 43%, with most sources falling within a more narrow range between like 30% to 35%,” said Jonathan Tsao, a project manager at CHRT.
It’s not yet clear which demographics are more or less susceptible to long COVID, though researchers are gaining clarity on that issue.
“The risk factors for getting long COVID are somewhat similar to those people who are at increased risk for severe disease,” said Dr. Liam Sullivan, an infectious disease specialist at Spectrum Health. “That being said, there’s a lot of people who’ve had mild COVID cases who have had issues with long COVID as well. So that’s not really been fully delineated yet.”
A Swedish study of more than 205,000 COVID patients founds that 32% of those admitted to an ICU developed long COVID. That’s compared to 6% of those hospitalized but not placed into intensive care, and 1% of outpatients.
Other groups that have reported disproportionate levels of long COVID are women, individuals 40 to 54, and persons with preexisting conditions, according to a 2021 study conducted in California and published by the CDC.
In Michigan, CHRT found women were four times as likely to report long COVID, and diabetics were twice as likely, compared to their counterparts.
Does the vaccine offer protection against long COVID?
A study published last month in Nature Medicine used 2021 Veterans Affairs health records to assess potential vaccine-induced protection against long COVID. The St. Louis, Missouri study determined COVID vaccination reduced risk of long COVID by about 15%.
It was one of, if not the largest, study to date. Researchers looked at records from 34,000 vaccinated people with breakthrough infections, 113,000 non-vaccinated people who got COVID, and more than 13 million people who had not gotten COVID.
The study revealed no difference in specific lingering symptoms or the severity of symptoms.
Dr. Sullivan said you have to be careful extrapolating those results to the general population however, when the study population were veterans with an average age in their 60s with underlying risk factors.
“Getting vaccinated doesn’t eliminate your risk for long COVID,” he said. “You still have risk for long COVID; what is starting to probably become clear is the risk is probably lower and that people don’t get quite as severe long COVID, but that question still has to be more fully answered.”
Sullivan said he anticipates the results of a larger study being conducted by CDC and some partner universities to better define and understand the scope of long COVID.
What’re the economic impacts of long COVID?
The latest Cover Michigan Survey found long haulers are more likely to be in a worse financial situation than a year ago, compared to those who recovered from COVID and those who never got infected.
Because long haulers may be unable to function at their pre-COVID capacity, they are more likely to take longer medical leave, work reduced hours, have their salary reduced, or quit their jobs, researchers found.
A national survey of more than 1,000 COVID patients found that 44% of workers experiencing long COVID reduced their weekly work hours. A majority of respondents said they needed to take medical leave due to long COVID symptoms.
Researchers who analyzed Michigan’s long COVID data said there’s a need for further study on the impact of state-wide efforts to assist long haulers. They recommend:
- Further research to understand the health and economic impacts of long COVID in Michigan, as well as funding programs;
- Development of funding programs, policies and approaches to bolster existing clinical care resources for long haulers;
- Organization of cross-sector partnerships to address the impact of long COVID across the state.
By publishing its survey results, CHRT researchers said they hope to raise awareness among lawmakers and business leaders as to the prevalence of long haulers, as well as for individuals who are suffering and feeling like they’re alone with their long-term symptoms.
“We want to raise an alarm, raise a flag to say ‘hey, this is potentially going to be and could be a really big deal for policymakers, for the state, for the economy, for the health care system and we need to be prepared,” Riba said.
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