Since 2020, the condition known as Long COVID-19 has become a widespread disability affecting the health and quality of life of millions of people around the world, costing economies billions of dollars due to reduced employee productivity and an overall reduction in the workforce.
The intense scientific effort sparked by Long COVID has resulted in over 24,000 scientific publications, making it the most studied health condition in any four-year period in recorded human history.
Long COVID is a term used to describe a range of long-term health effects caused by infection with the SARS-CoV-2 virus, ranging from persistent respiratory symptoms such as shortness of breath, to debilitating fatigue and brain confusion that limit the ability to work, to conditions such as heart failure and diabetes that are known to last a lifetime.
I am a physician-scientist who has been immersed in Long COVID research since the early days of the pandemic. I have testified as an expert witness on Long COVID before the U.S. Senate, published numerous papers on the subject, and been named one of TIME Magazine’s 100 Most Influential People in Medicine for 2024 for my work in this field.
In the first half of 2024, a series of reports and scientific papers on long COVID have been published, providing further clarity on this complex pathology, including notably insights into how COVID-19 can cause extensive damage to many organs even years after the initial viral infection, as well as new evidence of viral persistence and immune dysfunction that can last for months or even years after the initial infection.
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How long will COVID’s effects on the body last?
New research that my colleagues and I published in the New England Journal of Medicine on July 17, 2024, shows that the risk of long COVID has decreased over the course of the pandemic. In 2020, when ancestral strains of SARS-CoV-2 were dominant and vaccines were not available, about 10.4% of adults infected with COVID-19 developed long COVID. By early 2022, when Omicron family variants became dominant, that rate dropped to 7.7% in unvaccinated adults and 3.5% in vaccinated adults. In other words, unvaccinated people were more than twice as likely to develop long COVID.
While researchers like me don’t yet have hard numbers on current rates in mid-2024 because it takes time for long COVID cases to show up in the data, the influx of new patients into long COVID clinics is similar to 2022.
This decline was found to be the result of two main factors: the availability of a vaccine and changes in the characteristics of the virus, which may have made it less likely to cause a severe acute infection and reduced its ability to persist in the human body long enough to cause chronic disease.
Although the risk of developing long COVID is decreasing, even a 3.5% risk is substantial. New and reinfections with COVID-19 will lead to millions of new long COVID cases, adding to the already staggering numbers of people suffering from the condition.
Estimates from the first year of the pandemic suggest that at least 65 million people worldwide have long COVID. My team, along with a group of other leading scientists, will shortly publish updated estimates of the global burden of long COVID and its impact on the global economy through 2023.
Additionally, a major new report by the National Academies of Sciences, Engineering, and Medicine details all of the health effects that make up Long COVID. The report was commissioned by the Social Security Administration to understand how Long COVID will affect disability benefits.
The report concludes that Long COVID is a complex chronic disease that can cause more than 200 health effects across multiple body systems, including the onset of new and exacerbated conditions.
Long COVID can affect people across the lifespan, from children to the elderly, and across race, ethnicity, and baseline health conditions. Importantly, more than 90% of people with long COVID had mild COVID-19 infection.
The National Academy of Sciences report also concludes that long COVID-19 can result in consequences such as an inability to return to work or school, reduced quality of life, reduced ability to perform daily activities, and declines in physical and cognitive functioning for months to years after initial infection.
The report notes that many of the health effects of long COVID, such as post-exertional fatigue, chronic fatigue, cognitive impairment and autonomic dysfunction, are not currently included on the Social Security Administration’s list of disabilities but can have a significant impact on an individual’s ability to work or participate in school.
long way to go
Additionally, health problems from COVID-19 can last for years after initial infection.
A large study published in early 2024 showed that people with even mild SARS-CoV-2 infections experience new health problems related to COVID-19 within three years of their initial infection.
These findings are consistent with other studies showing that the virus persists in various organ systems for months to years after COVID-19 infection. Studies have also shown that the immune response to infection is still prominent 2-3 years after a mild infection. Together, these studies may explain why SARS-CoV-2 infections from years ago can cause new health problems long after the initial infection.
Important progress has also been made in understanding the pathways by which Long COVID wreaks havoc on the human body: Two preliminary studies in the U.S. and the Netherlands have shown that when researchers transfer autoantibodies (antibodies produced by a person’s immune system that target their own tissues and organs) from people with Long COVID to healthy mice, the animals begin to show symptoms similar to Long COVID, such as muscle weakness and poor balance.
These studies suggest that an abnormal immune response likely responsible for the generation of these autoantibodies may underlie long COVID and that removing these autoantibodies may hold promise as a potential treatment.
An ongoing threat
Despite overwhelming evidence showing the widespread risks of COVID-19, many messages suggest it is no longer a threat to the general public. There is no empirical evidence to support this, but this misinformation has permeated public discourse.
But the data tells a different story.
COVID-19 continues to surpass influenza in cases, hospitalizations, and deaths, and causes more serious long-term health problems. Downplaying COVID-19 as a minor cold or treating it like the flu is unrealistic.
