Several years into the pandemic, COVID-19 continues to deeply impact our society; at the time of publication of this review, 98.8 million cases in the United States have been reported to the Centers for Disease Control and Prevention (CDC).1 Although many people recover well from infection, there is mounting concern regarding long-term sequelae of COVID-19. These long-term symptoms have been termed long COVID, among other names.
What exactly is long COVID?
The CDC and National Institutes of Health define long COVID as new or ongoing health problems experienced ≥ 4 weeks after initial infection.2 Evidence suggests that even people who have mild initial COVID-19 symptoms are at risk for long COVID.
Available data about long COVID are imperfect, however; much about the condition remains poorly understood. For example, there is little evidence regarding the effect of vaccination and viral variants on the prevalence of long COVID. A recent study of more than 13 million people from the US Department of Veterans Affairs database did demonstrate that vaccination against SARS-CoV-2 lowered the risk for long COVID by only about 15%.3
Persistent symptoms associated with long COVID often lead to disability and decreased quality of life. Furthermore, long COVID is a challenge to treat because there is a paucity of evidence to guide COVID-19 treatment beyond initial infection.
Because many patients who have ongoing COVID-19 symptoms will be seen in primary care, it is important to understand how to manage and support them. In this article, we discuss current understanding of long COVID epidemiology, symptoms that can persist 4 weeks after initial infection, and potential treatment options.
Prevalence and diagnosis
The prevalence of long COVID is not well defined because many epidemiologic studies rely on self-reporting. The CDC reports that 20% to 25% of COVID-19 survivors experience a new condition that might be attributable to their initial infection.4 Other studies variously cite 5% to 85% of people who have had a diagnosis of COVID-19 as experiencing long COVID, although that rate more consistently appears to be 10% to 30%.5
A study of adult patients in France found that self-reported symptoms of long COVID, 10 to 12 months after the first wave of the pandemic (May through November 2020), were associated with the belief of having had COVID-19 but not necessarily with having tested positive for anti-SARS-CoV-2 antibodies,6 which indicates prior COVID-19. This complicates research on long COVID because, first, there is no specific test to confirm a diagnosis of long COVID and, second, studies often rely on self-reporting of earlier COVID-19.
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