More than 6 years after the COVID-19 pandemic began, its effects have continued. In March 2024, roughly 17 million adults (7% of all U.S. adults) reported currently having symptoms consistent with long COVID, a chronic condition characterized by persistent symptoms lasting 3 months or longer after infection. Long COVID can affect any system or organ in the body. Symptoms of long COVID include chronic fatigue, brain fog, difficulty concentrating, severe tiredness after exercise, lightheadedness and palpitations when standing, and many other problems. Those chronic symptoms often make it difficult for people to go to work or school.
As a result, long COVID imposes substantial disability. In fact, researchers have estimated that years lived with disability attributable to long COVID is comparable to other common diseases like Alzheimer's and asthma. In addition to the immediate effects on patients and their families, that disability translates into profound economic losses. Economists estimated in 2022 that the costs of long COVID will result in more than $3 trillion lost to society over 5 years, either through reduced quality of life and increased medical care or through lost economic productivity.
The Disconnect
However, research suggests long COVID may be underdiagnosed. Millions of Americans are thought to be suffering but not receiving appropriate clinical care. Furthermore, even now, well after the acute phase of the COVID pandemic has passed, an estimated 30,000 Americans are newly diagnosed with long COVID each year. But this is far fewer than expected, based on 2023 data. Thus, long COVID appears to have become a hidden cause of disease and disability.
When research suggests that as many as one in six patients with COVID-19 may develop post-acute sequelae but those statistics are inconsistent with what doctors are reporting, many start to deny the seriousness of long COVID. This, in turn, lays the groundwork for an inadequate response from policymakers. In fact, in February 2025, the Trump administration ended the Secretary's Advisory Committee on long COVID and closed the Office of Long COVID Research and Practice.
Understanding this disconnect between what research suggests and what doctors are seeing is of critical importance if we are to respond appropriately to the needs of those experiencing long COVID. We studied the possible reasons for this gap to answer a specific question: if millions of Americans supposedly have the disease, where are they?
First, long COVID may be ignored by some patients or can be misdiagnosed or undiagnosed by clinicians. The disease has a wide range of symptoms and severity. Many people with long COVID may have mild symptoms that do not limit their daily activities. As a result, they may never seek medical attention. However, anywhere from 20% to 65% of patients with long COVID report symptoms that are activity limiting. Because there is no lab test for long COVID, doctors may misdiagnose symptoms with other conditions such as depression, low thyroid levels, vitamin deficiencies, chronic anxiety, or early dementia. A recent study reported that among older adults, symptoms of long COVID may be difficult to distinguish from symptoms often attributed to aging. Among healthcare workers, long COVID can even be mistaken for severe occupational burnout.
Second, there is no simple cure for long COVID. While there are effective treatments like occupational therapy to help people manage their energy use and medications like fluvoxamine to reduce fatigue, these treatments do not work the same for everyone. Because of the limited treatment options, many patients may not consider doctors helpful and may instead turn to self-treatment.
Third, how researchers measure the frequency of long COVID differs from how it is diagnosed in practice. Doctors have a few minutes during a clinical encounter to make a diagnosis, while researchers use detailed criteria and checklists. To make things more complicated, how doctors classify the disease in the medical record matters. Many doctors may be unaware of the specific diagnosis code for long COVID or may simply classify the diagnosis based on symptoms (e.g., fatigue). One study recently showed that less than half of hospitalized patients that met criteria for long COVID were correctly diagnosed by clinicians.
Finally, while long COVID can lead to substantial and persistent symptoms, it is worth remembering that some people do recover. In fact, as many as 25% of patients with long COVID will recover within 2 years. Therefore, pinning down one estimate of the number of Americans with long COVID at any given time can be tricky.
Why Understanding the Burden of Long COVID Matters
More than $1.6 billion has been invested in long COVID research in the U.S. Millions more have been invested to expand access to care for patients with long COVID, including a few specialized clinics. Still, research has estimated that long COVID receives only a fraction of the funding warranted by the level of disability it causes. Advocates continue to call for substantially more funding, particularly given the $3 trillion estimated economic burden of the disease.
We need to unite in how we diagnose long COVID, how we monitor its complications, and how we measure it at the population level. The CDC should launch a working group to address long COVID and provide evidence-based recommendations for a public health response and medical care. That working group should include public health experts, patient advocates and families, as well as the scientists working to find a cure. Until then, we run the risk of either inappropriately allocating precious health resources or abandoning millions of people who are suffering.