"Long COVID" is a term coined by patients early in the pandemic to describe the broad number of issues they were experiencing after infection. These post-COVID conditions are a wide range of new, returning, or ongoing physical and mental health problems that some people experience after being infected with the virus that causes COVID-19. Most people with COVID-19 get better within a few days to a few weeks after infection, so at least four weeks after infection is the start of when post-COVID conditions could first be identified. Anyone who was infected can experience post-COVID conditions. Most people with post-COVID conditions experienced symptoms days after first learning they had COVID-19, but some people who later experienced post-COVID conditions did not know when they got infected.
There is no test that determines if your symptoms or condition is due to COVID-19. Post-COVID conditions are not one illness. Your healthcare provider considers a diagnosis of post-COVID conditions based on your health history, including if you had a diagnosis of COVID-19 either by a positive test or by symptoms or exposure, as well as doing a health examination.
Post-COVID conditions are associated with a spectrum of physical, social, and psychological consequences, as well as functional limitations that can present substantial challenges to patient wellness and quality of life.
Figure Source: Causal model of interaction of viral persistence, autoimmunity, latent viral reactivation, and tissue damage and dysfunction as root cause drivers of Long COVID; in Iwasaki A, Putrino D. Why we need a deeper understanding of the pathophysiology of long COVID. Lancet Infect Dis. 2023;23(4):393-395.
In April 2020, shortly after the beginning of the pandemic, anecdotal reports from patients started to emerge that previously healthy individuals were experiencing lingering symptoms and were not fully recovering from an infection with SARS-CoV-2. These patients started to refer to themselves as “Long Haulers,” and they coined the term “Long COVID.” This early recognition by the patient community, and their efforts to organize, colloquially name the condition, and alert the world to study it, galvanized the scientific community to pursue research programs in this area, which in a short period of time have resulted in substantial conceptual advances and significant breakthroughs.
“Long COVID is broadly defined as signs, symptoms, and conditions that continue or develop after initial COVID-19 or SARS-CoV-2 infection. The signs, symptoms, and conditions are present four weeks or more after the initial phase of infection; may be multisystemic; and may present with a relapsing-remitting pattern and progression or worsening over time, with the possibility of severe and life-threatening events even months or years after infection. Long COVID is not one condition. It represents many potentially overlapping entities, likely with different biological causes and different sets of risk factors and outcomes.”
This working definition was developed by the U.S. Department of Health and Human Services in collaboration with other departments including with subject matter experts at HHS Office of the Secretary, CDC, and NIH and coincident with engagement of patient groups, medical societies, and experts inside and outside the government.
The definition builds on CDC’s definition of Post-COVID-19 Conditions (PCC), conceptually first described by CDC in November 2020 and first labeled PCC in February 2021. Terms and definitions for these conditions have evolved since the beginning of the pandemic and will continue to evolve as we learn more about the symptoms and conditions associated with Long COVID. In addition to Long COVID and PCC, an additional term had emerged in parallel and is in general usage in the United States: Post-Acute Sequelae of SARS-CoV-2 infection (PASC).
While Long COVID is largely a lay term, PCC and PASC are two scientific technical terms. PCC covers a wide range of health consequences that are due to all effects of COVID-19, including secondary and tertiary effects. PASC refers to the direct and indirect consequences of SARS-CoV-2 on human health.
NVSS National Vital Statistics Reporting Guidance, Expanded February 2023
In the acute phase, clinical manifestations and complications of COVID-19 of varying degrees have been documented, including death. However, patients who recover from the acute phase of the infection can still suffer long-term effects. Post-acute sequelae of COVID-19 (PASC), commonly referred to as “long COVID,” refers to the long-term symptoms, signs, and complications experienced by some patients who have recovered from the acute phase of COVID-19.
Emerging evidence suggests that severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus that causes COVID-19, can have lasting effects on nearly every organ and organ system of the body weeks, months, and potentially years after infection.
Documented serious post-COVID-19 conditions include cardiovascular, pulmonary, neurological, renal, endocrine, hematological, and gastrointestinal complications, as well as death.