Contested illnesses like long COVID reveal the limits of conventional medicine

Long COVID symptoms, such as fatigue, shortness of breath, cognitive difficulties, erratic heart rate, headache and dizziness, can be debilitating and wide-ranging. There is uncertainty about what ultimately causes long COVID and how to adequately respond to it.

In conventional medicine, illnesses without definitive markers of disease are often described as "medically unexplained." As a medical anthropologist who has studied the controversy over whether treated Lyme disease can become chronic, I've been struck by the similarities between long COVID and other contested illnesses like chronic Lyme disease and myalgic encephalomyelitis, more familiarly known as chronic fatigue syndrome.

Patients with contested illnesses can often feel unseen and unheard, and their providers often feel frustrated that they can't do more. As patient advocacy movements have emerged, so has scientific disagreement about what causes these illnesses and how to address them. Contested illnesses pull back the curtain on medicine itself: how it understands the human body, what counts as evidence and how medicine draws on that evidence to produce medical truths.

Long COVID has a bigger spotlight than other contested illnesses and was recognized much faster. Post-COVID clinics have been established in nearly every state, the National Institutes of Health have invested $1.15 billion to study it, and it's now included in the Americans With Disabilities Act. Long COVID has brought increased attention to other marginalized illnesses, along with hope that the needle might finally be moved on overdue research and funding.

At the heart of conventional medicine is a foundational distinction between symptoms and signs. Symptoms like fatigue and joint pain are subjective markers of disease, while signs like fever and arthritis are considered objective markers. Unlike symptoms, signs can be observed and measured by a practitioner, often with the aid of technologies such as blood tests and radiologic imaging.

When it comes to making a diagnosis, signs trump symptoms. This enduring hierarchy can be traced to the late 18th and early 19th centuries in the U.S. and Europe, when physicians who had relied on external symptoms for diagnosis shifted to a focus on internal anatomy and pathology by using technologies like microscopes. The French philosopher Michel Foucault observed that during that time, medicine transitioned from a practice in which the physician asked, "What's the matter with you?" to a practice in which the physician asked, "Where does it hurt?" The first question invites a patient's description of symptoms; the second question leads to a location on the patient's body that can be observed and measured by the physician.

The diagnostic importance of signs over symptoms was further cemented in the late 1980s and early 1990s with the establishment of evidence-based medicine. It aims to standardize clinical care through guidelines and a pecking order of scientific evidence, with objective evidence of randomized controlled trials at the top and subjective evidence of expert opinion at the bottom. The shift to evidence-based medicine solidified objective evidence as the strongest and most legitimate basis for the diagnosis of disease and reinforced contested illnesses as "medically unexplained," a term that has often been used to describe physical distress caused by mental illness.

The death toll from COVID-19 has been staggering and disproportionate. But medicine's emphasis on mortality over morbidity has consequences for how suffering is measured as well as the efforts undertaken to prevent disease transmission and the thresholds used for determining when the pandemic is over. If we expand suffering's metric to include long COVID morbidity, then individual and collective decisionmaking would not only take into account the risk of hospitalization and death but would also include the risk of long COVID.

When patients with contested illnesses don't find answers in conventional medicine, they often seek out the symptom-centered practices of complementary and alternative medicine. One mainstream Lyme physician I interviewed surmised that although he did not "believe in alternative medicine," patients' gravitation toward it was a result of conventional medicine's "failure to treat the symptoms that they have." Validating patients' symptomatic experience, even if the cause is unknown, is one possible remedy.

Patients with contested and chronic illnesses also tend to have long medical histories. These patients need longer than 15 minutes to tell their story, and providers need more than 15 minutes to listen to them. A broad-scale investment in primary care that would allow providers to offer longer appointments that are fully covered by insurance would help to address this need. Additionally, medical schools should introduce a social science-informed understanding of contested illnesses. Despite seeming marginal, "medically unexplained" illnesses are actually some of the most frequently seen conditions in primary care. The more familiar physicians are with these illnesses, the fewer opportunities there will be for misunderstanding.

"Acknowledging uncertainty" — what long COVID patients have called for — is a fitting refrain for our times. As much as they wanted answers, the Lyme patients I interviewed also wanted physicians who could admit what they didn't know. Starting with what we don't know — and leading with humility and empathy — seems like a good place to begin.