Last week, one of the reader questions I answered addressed Long COVID, the condition in which people have COVID-related symptoms for weeks or months after their initial coronavirus infection. One reader had asked about monitoring for Long COVID patients (also called long-haulers); I later received another question about the risks of Long COVID after vaccination.
These questions made me realize that I’ve devoted very little space to Long COVID in the COVID-19 Data Dispatch—even though I consider it one of the biggest COVID-19 data gaps in the U.S. Though it’s now been well over a year since the first Long COVID patients were infected, there is still so much we don’t know about the condition.
For example, we don’t know a very rudimentary number: how many people in the U.S. are struggling with Long COVID. We also don’t have a clear, detailed picture of Long COVID symptoms, or how these symptoms arise from a coronavirus infection, or how they impact the daily lives of Long COVID patients.
Why does this massive data gap exist? Long COVID studies are challenged by the lack of standardized patient data in the U.S., making it difficult to identify symptom patterns across large groups of people. We face a similar problem in tracking breakthrough cases, demographic information, and other COVID-19 trends.
Plus, thanks to limited COVID-19 testing in the U.S. throughout the pandemic (and restrictions on who could get tested, back in spring 2020), a lot of Long COVID patients never had a positive test result—making it difficult for them to get a formal diagnosis. And many of the Long COVID studies that have been conducted focus on patients who had a positive COVID-19 test or were hospitalized for the disease, thus narrowing much of our clinical data to a small subset of the actual Long COVID population.
As I noted last week, the National Institutes of Health (NIH) has set up a major research initiative to study Long COVID. This initiative, called RECOVER, is poised to become our best source for Long COVID data in the future. But it’s in early stages right now, beginning to distribute funding to different research groups and recruit Long COVID patients for study. It could be years before we get results.
All of that said, there are still a few things we know about Long COVID based on research thus far. Here’s a roundup of twelve key statistics.
- Between 10% and 30% of coronavirus infections lead to Long COVID. This statistic comes from the NIH’s RECOVER Initiative website; it summarizes findings from past studies. Consider: 30% of the 44.2 million Americans with a documented COVID-19 case amounts to 13.3 million people with Long COVID. Even 10% of those 44.2 million would amount to 4.4 million people.
- Some studies suggest that as many as one-third of COVID-19 patients may have persistent or returning symptoms. A recent study of electronic health records in the U.S. and U.K., run by scientists at the University of Oxford, suggests that the true share of COVID-19 patients who contract Long COVID is on the higher end of that 10%-30% estimate that the NIH provides. This new study found that 36% of COVID-19 patients (among a sample size of 270,000) had symptoms three and six months after their diagnosis.
- Long COVID may manifest with over 100 different potential symptoms. There is a Long COVID paper that I personally come back to, whenever I want to see a clear picture of the many ways that this condition can impact patients. The paper, published in The Lancet in July, reports results from a survey of over 3,000 Long COVID patients conducted by the Patient-Led Research Collaborative. According to this survey, Long COVID patients may suffer from about 100 possible symptoms, including systemic, reproductive, cardiovascular, musculoskeletal, immunologic/autoimmune, head/eyes/ears/nose/throat, pulmonary, gastrointestinal, and dermatologic symptoms.
- Long COVID symptoms may change over time. The Patient-Led Research Collaborative survey found that some patients may have changing symptoms, or relapses brought on by different activities. One very common Long COVID symptom is Post-Exertional Malaise, a condition in which patients experience a relapse after physical or mental exertion, even if that exertion is relatively minor.
- Some Long COVID patients have been sick for over 18 months. The Patient-Led Research Collaborative survey covers symptoms over a course of seven months, but some Long COVID patients have been suffering for far longer. Some patients who initially contracted the coronavirus in spring 2020, during the first wave in the U.S., have now been sick for 18 months or more.
- Many Long COVID patients are unable to work. According to the Patient-Led Research Collaborative survey, almost half of the Long COVID patients who responded (45%) “required a reduced work schedule, compared to pre-illness.” Another 22% were not working at the time of the survey because of Long COVID. Other studies have backed up the findings from this survey. At this point in the pandemic, some Long COVID patients are struggling to receive accommodations from their employers, even though the condition is recognized as a disability at the federal level.
- Long COVID can occur at all age ranges, but is documented most in younger and middle-age adults. Among respondents to the Patient-Led Research Collaborative survey, about 24% were in their thirties, 31% in their forties, and 25% in their fifties—though patients ranged in ages from 18 to over 80. This survey and others have also found that Long COVID seems to be more common for women; this pattern aligns with other post-infectious conditions, like chronic fatigue syndrome and chronic Lyme disease.
- Long COVID may lead to long-term neurological issues. This past summer at the Alzheimer’s Association International Conference, a few researchers presented findings on Long COVID and Alzheimer’s. Brain scans of COVID-19 patients, along with observations of patients’ prolonged symptoms, suggest that adults who suffer from Long COVID may have an increased risk of Alzheimer’s later in life. Severe COVID-19 patients in their sixties and seventies are already starting to see symptoms matching early-onset Alzheimer’s, one researcher told NPR.
- Autoimmune response may be one cause for Long COVID symptoms. While scientists are still working to determine exactly how a coronavirus infection may lead to numerous symptoms, research thus far suggests that overreaction of the immune system could be a major player. Some clinicians who work with Long COVID patients have developed treatments based on dysautonomia, medical conditions caused by immune and autonomic nervous system issues.
- About 5,200 children in the U.S. have been diagnosed with MIS-C, and 46 have died. MIS-C stands for Multisystem Inflammatory Syndrome in Children. The condition follows a COVID-19 infection in rare cases, leading to inflammation of different parts of the body. While this condition is not directly comparable to Long COVID, scientists think it may have similar causes. The condition has disproportionately impacted children of color in the U.S.: out of 5,200 cases, 61% are Black or Hispanic/Latino.
- The risk of Long COVID is dramatically lower after a breakthrough infection, even if you contract the coronavirus. A recent study published in The Lancet found that vaccinated patients who later had a breakthrough COVID-19 case were about half as likely to report symptoms after four weeks, compared to unvaccinated patients who had a non-breakthrough COVID-19 case. Plus, vaccinated people are already far less likely to contract the coronavirus in the first place, because vaccination reduces risk of infection. Commenting on the study, NIH Director Dr. Francis Collins called it “encouraging news,” though he cautioned that more research is needed on this topic.
- Vaccination may help alleviate COVID-19 symptoms for Long COVID patients. In addition to reducing one’s risk of developing Long COVID, vaccination can alleviate symptoms for Long COVID patients. A recent preprint, posted online at the end of September, found that Long COVID patients who got vaccinated were about twice as likely to completely recover, compared to unvaccinated patients. “Overall, this study adds to growing evidence that vaccines can improve symptoms and lessen the disease impact in Long COVID,” wrote Long COVID researcher Dr. Akiko Iwasaki, sharing the study on Twitter.
To me, these Long COVID statistics—along with everything we still don’t know about the condition—provide a strong argument for vaccination. Long COVID can impact people who were young and healthy before they were infected, completely messing up their lives for months or even years. It surprises me that public health and political leaders don’t discuss this condition more when they tell people to get vaccinated.
As for continued research: the NIH’s RECOVER Initiative has received over $1 billion in funding from Congress, and it’s just getting started on setting up studies. If you’re interested in learning more about the research—or signing up to participate in a RECOVER study—you can sign up for email alerts on the NIH website.