Abstract:
The recognition of Long Covid has renewed efforts to understand other infection-associated chronic conditions (IACCs). Here, we describe how studies of Long Covid and other IACCs might inform one another. We argue for the importance of a coordinated research agenda addressing these debilitating illnesses.
INTRODUCTION
For nearly a century, individuals with medically unexplained chronic conditions, particularly those thought to be attributable to presumably transient infectious pathogens, have faced bewilderment, skepticism, or outright dismissal from the medical establishment. Debilitating symptoms lasting for years have been reported after acute infections with viruses [enterovirus, Epstein-Barr virus (EBV), influenza virus, Ebola virus, dengue virus, chikungunya virus, West Nile virus, and severe acute respiratory syndrome coronavirus 1 (SARS-CoV)], bacteria (
Borrelia and
Anaplasma), and protozoa (
Giardia) (
1). Myalgic encephalomyelitis (ME), sometimes referred to as chronic fatigue syndrome (CFS), is perhaps the best example of a disabling syndrome that many experts believe follows an acute, often undiagnosed viral infection. Several names have been applied to these syndromes, including post-acute infection syndromes (PAIS), infection-associated chronic illnesses, and infection-associated chronic conditions (IACCs). Here, we will use IACCs.
Despite consistent reports regarding these conditions dating back nearly 100 years (
2–
4), the biomedical establishment has made limited progress in defining the epidemiology, natural history, and pathogenesis of most IACCs. No diagnostic tests are available, no widely accepted treatments exist, and industry engagement on finding a cure has been limited. In her 1996 book
Osler’s Web, investigative journalist Hillary Johnson catalogued the challenges facing ME/CFS research (
5), which can be applied to many IACCs. Barriers to progress included the inability to fit ME/CFS into existing disease paradigms, variability and inconsistency in case ascertainment, skepticism on the part of many clinicians and scientists, and intense stigma that kept many of those affected from seeking medical care. William Osler, the “father of modern medicine,” emphasized the importance of listening to patients to discern important features of their condition. However, contemporary medical practice relies heavily on diagnostic tests, which are currently inadequate to confirm the presence of an IACC. This results in people being neglected or misdiagnosed and prevents them from receiving appropriate care and support.
The year 2020 has the potential to be a turning point in this story. Shortly after the COVID-19 pandemic began, reports of individuals with prolonged COVID-attributed symptoms emerged, a condition now often referred to as Long Covid. The synchronicity of the inciting infection, universality of the exposure, and visibility, aided by social, popular, and scientific media (
6), resulted in the ideal environment for a coordinated effort to understand this new IACC. Substantial investment in scientific effort is starting to pay off, with real progress in defining the epidemiology, natural history, and biology of Long Covid now emerging. After a Congressional appropriation, the US National Institutes of Health rapidly launched the Researching COVID to Enhance Recovery (RECOVER) initiative, which is the first large-scale program aimed at tackling an IACC. The progress to date has been hard-won, however, in part because there is no widely accepted clinical definition, biomarker, or diagnostic test for Long Covid. However, clinical trials, slow to start, are now being pursued in earnest. Although there is no guarantee that this momentum will be sustained without dedicated scientific and financial commitments (
7), there is reason to believe that efforts to understand Long Covid have the potential to draw attention to, reframe, and revitalize the efforts to study other IACCs.
High-quality academic reviews of Long Covid are multiplying rapidly (
8–
12). Our goal in this Viewpoint is not to provide a comprehensive overview of the field but rather to place efforts to study Long Covid in the context of other IACCs. In doing so, we hope to outline several areas that we believe will require consideration as the field attempts to make progress in navigating what has been described as a “labyrinth” (
5).
Source: Michael J. Peluso
et al. Infection-associated chronic conditions: Why Long Covid is our best chance to untangle Osler’s web. Sci. Transl. Med.16,eado2101(2024). DOI:10.1126/scitranslmed.ado2101