The current concern for “long COVID” underscores an increasing recognition of chronic illnesses that appear to arise from infectious diseases. This overlooked, growing public health problem often includes a patient history of infection by viral or bacterial pathogens followed by long-lasting and often debilitating symptoms including severe fatigue, cognitive impairment, and multi-organ dysfunction. Examples of infection-associated chronic illnesses include:
- Long COVID or post-acute sequelae of COVID-19: Between 10 to 30% of patients infected with SARS-CoV-2 develop chronic symptoms that lead to a diagnosis of long COVID. This estimation translates to a disease burden of between 7.7 million and 23 million patients who will be living with long COVID by February 2022.
- Myalgic encephalomyelitis/chronic fatigue disease (ME/CFS): ME/CFS onset is often associated with a prior, unidentified infectious episode. Approximately 1.7 to 3.3 million patients in the U.S. are diagnosed with ME/CFS and experience chronic, multi-organ symptoms.
- Persistent or post-treatment Lyme disease: Between 10-20% of Lyme disease patients develop persistent and debilitating symptoms after standard antibiotic treatment There are approximately 2 million patients in the U.S. living with persistent or post-treatment Lyme disease syndrome.
- Multiple sclerosis: A strong association of multiple sclerosis with Epstein-Barr virus infection was recently reported. In the US, more than 700,000 patients are living with multiple sclerosis.
In addition to the debilitating physical impact on patients, chronic illnesses present broader societal impacts. For example, between 31-70% of COVID patients remain absent from work after the acute phase of the disease and long COVID may be responsible for 1.6 million fewer full-time workers in the U.S. labor market. In the United Kingdom, an estimated economic loss of 32.2 billion pounds over 10 years will be attributable to permanent injury from COVID-19 in adults, 92% of which may be due to long COVID.
Given the commonality in chronic symptoms among long COVID, persistent Lyme disease syndrome, ME/CFS, multiple sclerosis and other conditions, it is not surprising to find similarities in the leading hypotheses for the explanation of these illnesses; e.g., pathogen or antigen persistence, immune response dysregulation, altered neurologic function, and altered microbiome composition and activity. Researchers studying different infection-associated chronic illnesses face common challenges in identifying disease biomarkers and developing diagnostics and therapeutic options.
