Long COVID may be a more significant contributor to disability than previously thought, a study suggests.
One in ten (11%) of Americans suffer from long COVID, which is broadly defined as symptoms and conditions that persist or develop 3 months after acute infection.
Although the percentage of people who continue to experience complications weeks or months after testing positive is decreasing, 79% of those with long COVID report that the condition limits their day-to-day activities, according to the Kaiser Family Foundation (KFF) survey.
Authors of the new study published in Nature Medicine compared data from 138,818 veterans who got COVID-19 infection in 2020 to nearly six million individuals who never tested positive. The participants were followed for two years to estimate the risks of death and 80 complications linked to long COVID.
The researchers then translated the data on the long COVID burden into a metric called a disability-adjusted life year, or DALY. One DALY represents the loss of the equivalent of one year of full health due to premature mortality and the years lived with a disability.
The study found that long COVID contributed to 80.4 DALYs per every 1,000 non-hospitalized people and 642.8 DALYs per 1,000 hospitalized individuals. This makes long COVID a more disabling condition than cancer, which generates 50 DALYs for every 1,000 Americans, according to the Global Burden of Disease study.
Most DALYs due to long COVID were caused by musculoskeletal complications, endocrine disorders, and gastrointestinal issues.
The study also found that people who were not hospitalized during the acute phase of COVID-19 were still at an increased risk of death during the 91 to 180 days after the infection.
The risk for blood and pulmonary disorders, fatigue, gastrointestinal disorders, musculoskeletal disorders, and diabetes remained increased two years after the infection among the patients who had COVID-19 but were not hospitalized compared to those who never tested positive. Among those hospitalized, risks for most organ systems examined remained elevated at two years after SARS-CoV-2 infection.
However, the study analyzed an older population with an average age of over 60 years old, and the majority (about 90%) of the participants were men. Thus, the findings may not be applicable to younger or female populations. Moreover, the COVID-19 group did not include people who had the infection but were not tested, possibly resulting in an underestimation of risks.
The participants contracted COVID-19 while there were no vaccines, which appear to lower the risk of developing long COVID and reduce its severity, studies suggest.
While this study reveals the debilitating effects of long COVID, the pandemic is not over, and more longitudinal data is necessary to fully understand the impact of the disease.
- Nature Medicine. Postacute sequelae of COVID-19 at 2 years.
- Kaiser Family Foundation. Long COVID: What Do the Latest Data Show?
- JAMA Oncology. Cancer Incidence, Mortality, Years of Life Lost, Years Lived With Disability, and Disability-Adjusted Life Years for 29 Cancer Groups From 2010 to 2019.
- The British Medical Journal. Covid-19: Vaccination reduces severity and duration of long covid, study finds.
- Cambridge University Press. The effectiveness of coronavirus disease 2019 (COVID-19) vaccine in the prevention of post–COVID-19 conditions: A systematic literature review and meta-analysis