Research into long-haul COVID-19 may offer insights into other chronic diseases, disease expert says
As COVID-19 passes its first year in the United States, one area of interest is the long-term effects that the virus has on many who contract it. Sometimes called “long-haul COVID-19,” these long-term symptoms are thought to affect a significant portion of those who contract a COVID-19 infection and can be debilitating to those who suffer from one.
In a recent Los Angeles Times op-ed, Leroy Hood, MD, PhD, who specializes in gene sequencing technology development and is considered an insightful expert on disease, discusses long-haul COVID-19. Hood also discusses how research into long-haul COVID-19 is not only helping to resolve the symptoms that people are experiencing but also is offering insights into how to better treat other chronic conditions and immune system abnormalities that are triggered by infectious diseases.
Some Features of Long-Haul COVID-19
Between 40% and 75% of long-haulers describe a complex neurological constellation of symptoms and conditions, Hood writes. “These include fatigue, intense headaches, muscle weakness, difficulty sleeping, anxiety, poor concentration, memory loss and changes to the sense of taste and smell. Most have three or more symptoms, which indicates that long-haul COVID-19 likely affects multiple parts of the brain or multiple organ systems at once.”
Hood points out that while the severity of COVID-19 itself is often somewhat predictable based on the health of the individual who is infected, the same is not necessarily true for long-haul COVID-19. “Just as puzzling, many long-haulers never experienced severe COVID-19 or needed hospitalization,” Hood says. “Comorbidities, such as obesity, diabetes and heart disease, do not appear to be causal factors.”
Early Studies of Long-Haul COVID-19
Research shows that the prevalence of long-haul COVID-19 is higher than many initially thought. “A study in China found that 75% of hospitalized COVID-19 patients after six months reported at least one long-haul symptom,” Hood explains. “The conservative estimate from many sources is that at least 10% of COVID-19-infected individuals experience long-haul symptoms.”
Hood is part of a joint research team that includes the Institute for Systems Biology (ISB) and Swedish in Seattle. Hood’s team analyzed the immune responses of individuals who were infected with COVID-19 and used the information to acquire data that is increasing understanding of some fundamental principles of long-haul COVID-19.
Vaccination Questions Around Long-Haul COVID-19 and Treatment
“This kind of comprehensive immune analyses at the individual patient level may help answer fundamental questions,” Hood says, “such as what are the mechanisms of COVID-19 disease, both acute and long-haul? What kinds of new medicines or therapies are needed? Is it possible to predict who is susceptible and provide treatment before severe symptoms develop?”
The research team’s findings have already offered a potential treatment for patients who suffer from long-haul COVID-19. “One interesting effect recently observed is that some long-haulers who got vaccinated experienced rapid and complete remission of their symptoms,” Hood explains. “The percentage of those who respond positively to vaccination and the length of remission is unknown, but reports suggest that vaccination will be an important long-hauler treatment as well as a defense against COVID-19.”
In addition to gaining a better understanding of COVID-19 and its long-term effects, Hood believes that research in this area will contribute to a better understanding of other conditions.
“Understanding the immune system’s response to COVID-19 may even help us understand, diagnose and treat other complex chronic immune-related conditions,” Hood says. “This could be particularly true with illnesses with neurological symptoms common to long-haul COVID-19.”
Possibilities of Comprehensive Immune Analyses
The research team examined serial blood draws from 139 COVID-19 patients of all severities, from patients recovering at home to critically ill patients and in the ICU. From each blood sample, they measured thousands of proteins and metabolites to capture the environment of the circulating immune system, according to an ISB statement. They also measured thousands of genes and proteins from individual immune cells. Finally, they utilized novel computational methods to merge all of these observations together to provide an integrated view of COVID-19 infection during the week following initial diagnosis.
“Today, millions of people struggle with chronic conditions that may also be triggered by immune system abnormalities, whose origins are often unknown,” Hood adds. Hood says that this includes conditions such as “rheumatoid arthritis, multiple sclerosis, lupus, Lyme disease, chronic fatigue syndrome, Guillain-Barre syndrome and inflammatory bowel disease. Comprehensive immune analyses will almost certainly provide fundamental new insights into many of these diseases.”
Ultimately, the research into long-haul COVID-19 is set to provide valuable information that will help in the development of treatments for other diseases. “This new kind of analysis has the potential to advance understanding of disease mechanisms and accelerate holistic therapies for millions of long-haulers—and perhaps for people suffering from other chronic diseases as well,” says Hood.
As long-haul COVID-19 becomes more prevalent of a concern, and emerging research continues to provide more information about its effects, clinical laboratories bring to the table the ability to test for COVID-19 antibodies in those who have long-haul COVID-19 symptoms but are unsure if they were ever infected with SARS-CoV-2.
Laboratories may also find that, as research continues, new clinical laboratory tests could become available that provide clinical information on long-haul COVID-19, offer an opportunity to expand needed testing services, and result in enhanced patient care.
—By Caleb Williams, Editor, STAT Intelligence Briefings