Since its emergence in 2020, long COVID-19 has evolved into a significant global health challenge, affecting millions and exerting a profound impact on economies due to reduced workforce productivity. The intense focus on this condition has generated over 24,000 scientific publications, making Long COVID the most extensively researched health condition in any four years of recorded history.
Understanding Long COVID
Long COVID encompasses a range of long-term health effects following infection with the SARS-CoV-2 virus. These effects include persistent respiratory issues like shortness of breath, severe fatigue, brain fog, heart failure, and diabetes. These symptoms can significantly impair an individual’s ability to work and maintain quality of life. As a physician-scientist deeply involved in long COVID research, I have testified before the U.S. Senate on this condition and have been recognized for my contributions to understanding it.
Recent studies have shed light on how COVID-19 continues to affect various organs years after the initial infection. Research highlights ongoing viral persistence and immune dysfunction that can last months or even years. A notable study published in the New England Journal of Medicine in July 2024 revealed that the risk of Long COVID has decreased over time. Initially, in 2020, 10.4% of adults with COVID-19 developed long COVID. By early 2022, this rate had dropped to 7.7% among unvaccinated adults and 3.5% among vaccinated adults.
Declining Risks and Persistent Challenges
The decline in long COVID cases is attributed to the widespread availability of vaccines and changes in the virus’s characteristics, making it less likely to cause severe acute infections and potentially reducing its ability to persist in the human body. However, even a 3.5% risk is substantial. New COVID-19 infections continue to result in millions of long COVID cases, adding to the already significant number of affected individuals.
Initial estimates suggest that at least 65 million people globally have experienced long COVID. My team, along with other leading scientists, is preparing to publish updated estimates of the global burden of long COVID and its economic impact through 2023. A major report by the National Academies of Sciences, Engineering, and Medicine, commissioned by the Social Security Administration, details over 200 health effects of long COVID, including heart disease, cognitive impairment, strokes, dysautonomia, post-exertional malaise, gastrointestinal disorders, kidney disease, metabolic disorders, and immune dysfunction.
These health effects span all ages and demographics, with more than 90% of long COVID patients having experienced only mild initial infections. The report underscores the significant impact of long COVID on individuals’ ability to work, quality of life, and physical and cognitive function, often lasting for months or years after the initial infection.
Ongoing Research and Future Directions
Despite the extensive research, long COVID remains a complex and chronic condition. A large study published in early 2024 indicated that even those with mild initial infections experienced new health problems related to COVID-19 years later. This aligns with findings showing that the virus can persist in various organ systems long after the initial infection, and immune responses to the infection can be detected years later. Promising research is uncovering potential pathways by which long COVID affects the body.
Preliminary studies from the U.S. and the Netherlands suggest that auto-antibodies generated by the immune system in response to long COVID can cause symptoms when transferred to healthy mice. These findings hint at the possibility of treatments targeting these auto-antibodies. Despite these advancements, public perception of COVID-19 as a non-threatening issue persists, often downplaying the serious long-term health risks associated with the virus. The data, however, contradicts this narrative, showing that COVID-19 continues to cause more hospitalizations and deaths than the flu and leads to more severe long-term health issues.