Clinical Case Definition of Long COVID


Long COVID or post-COVID-19 is umbrella terms that refer to COVID-19 symptoms that persist beyond the initial phase of a SARS-CoV-2 infection. The absence of a formal definition for post-COVID-19 has made the research of this condition and its management challenging.

The World Health Organization (WHO) recently published a definition of post-COVID-19 according to input from a panel of researchers, patients, and clinicians. A standardized definition of post-COVID-19 will help advance research, facilitate awareness and acceptance, and aid diagnosis and management of this condition.

Depending upon the severity of symptoms, most individuals recover from COVID-19 within the first 3–4 weeks after contracting the SARS-CoV-2 virus. Yet, a significant number of individuals experience lingering COVID-19 symptoms for weeks and months after this initial or acute phase of the infection. People have collectively described these persistent COVID-19 symptoms with terms such as long COVID, “post-acute COVID-19,” or “post-COVID-19.”

Some of the common symptoms of long COVID include fatigue, breathing difficulties, insomnia, pain, and brain fog. Additionally, post-COVID-19 can adversely Trusted Source impact multiple organ systems Trusted Source, including the kidneys, lungs, pancreas, and heart. The lack of a standardized definition and consistent terminology for post-COVID-19 have been obstacles for researchers studying the condition and its clinical diagnosis and treatment.

There was a lack of awareness and scepticism Trusted Source about post-COVID-19 among the public and medical professionals when the initial cases of long COVID emerged. Consequently, individuals with persistent symptoms did not get the necessary medical care they required. Since then, researchers have conducted several studies to estimate the proportion of individuals with persistent symptoms and determine the risk factors and symptoms associated with post-COVID-19. Although there is more widespread awareness about post-COVID-19 now, the absence of a formal definition for the condition has led to inconsistencies in protocols by research groups studying this condition.

For instance, there is a lack of consensus about the time of onset and duration of post-COVID-19 symptoms. This has led to research groups using different time windows to estimate the incidence of long COVID. Similarly, the absence of consensus on the symptoms associated with long COVID has resulted in studies including or excluding certain symptoms, influencing the estimates of the incidence of the condition and its symptoms. The lack of a formal clinical case definition, which can provide criteria for diagnosing long COVID, has created challenges for healthcare professionals to diagnose and treat individuals with persistent symptoms.

Several organizations and societies have issued definitions for post-COVID to facilitate research and help the management of individuals with long COVID. However, a globally standardized definition has been lacking. The WHO used a protocol called the Delphi method to arrive at its definition of post-COVID. The Delphi method involves multiple rounds of surveying an expert panel to arrive at a consensus. The WHO panel consisted of clinicians, researchers, patient groups and policy-makers, representing different nations. After two rounds of surveys and a panel discussion, the WHO panel decided on the term “post-COVID-19” and the following definition:

“Post-COVID-19 condition occurs in individuals with a history of probable or confirmed SARS-CoV-2 infection, usually 3 months from the onset of COVID-19 with symptoms that last for at least 2 months and cannot be explained by an alternative diagnosis.”

“Common symptoms include fatigue, shortness of breath, cognitive dysfunction but also others, which generally have an impact on everyday functioning. Symptoms may be new onset, following initial recovery from an acute COVID-19 episode, or persist from the initial illness. Symptoms may also fluctuate or relapse over time.” Anxiety, depression, pain, and changes in hearing, smell, and taste were among the other symptoms that the definition included.

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Alina Grace            

Journal Manager

Asian Journal of Biomedical & Pharmaceutical Sciences