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Last reviewed: August 16, 2022
The following is a curated review of key information and literature about this topic. It is not comprehensive of all data related to this subject.
Some patients experience new, recurring or ongoing symptoms related to COVID-19 several weeks after the acute phase of infection (Nalbandian, March 2021; Hope, June 2022). These symptoms are referred to by many different names, including “long COVID,” “long-haul COVID,” “chronic COVID,” “post-COVID syndrome” and “post-acute COVID-19 syndrome,” as well as the research term “post-acute sequelae of SARS-CoV-2 infection (PASC).” The U.S. Centers for Disease Control and Prevention uses the umbrella term “post-COVID conditions” to capture health problems that occur 4 or more weeks after acute COVID-19 infection.
Because of the wide variety of symptoms that may be encompassed by post-COVID conditions, and the lack of a definitive diagnostic test, standardized case definitions have been challenging to develop. In 2021, the World Health Organization published a working clinical case definition of post-COVID conditions that was developed by Delphi consensus (an iterative survey of experts, patients and other stakeholders designed to create a consensus 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. A separate definition may be applicable for children.”
As noted previously, all-encompassing standardized definitions of post-COVID conditions remain elusive, which means studies of patients at risk for or experiencing post-COVID symptoms have important methodologic and analytic limitations. This includes difficulty identifying patients with post-COVID conditions in a consistent and systematic fashion and defining appropriate “control” populations for comparison. Given these limitations in individual studies, it is similarly challenging to draw definitive broad conclusions about the pathogenesis, epidemiology, prevention and management of post-COVID conditions based on data across different studies. Nevertheless, important insights about these and other aspects of post-COVID conditions continue to emerge and are shaping clinical decision-making, public health policy and research initiatives.
Here we highlight studies that contribute to our understanding of this evolving field.
- Distinguishing Features of Long COVID Identified Through Immune Profiling (Klein, August 2022 — preprint, not peer-reviewed)
- Markers of Immune Activation and Inflammation in Individuals With Postacute Sequelae of Severe Acute Respiratory Syndrome Coronavirus 2 Infection (Peluso, December 2021)
- SARS-CoV-2 Infection and Persistence Throughout the Human Body and Brain (Chertow, December 2021 — preprint, not peer-reviewed)
- Multiple Early Factors Anticipate Post-Acute COVID-19 Sequelae (Su, March 2022)
- Evolution of Antibody Immunity to SARS-CoV-2 (Gaebler, January 2021)
- Persistence, Magnitude, and Patterns of Postacute Symptoms and Quality of Life Following Onset of SARS-CoV-2 Infection: Cohort Description and Approaches for Measurement (Peluso, December 2021)
- Characterizing Long COVID in an International Cohort: 7 months of Symptoms and Their Impact (Davis, August 2021)
- More Than 50 Long-Term Effects of COVID-19: A Systematic Review and Meta-Analysis (Lopez-Leon, August 2021)
- Persistence of Somatic Symptoms After COVID-19 in the Netherlands: An Observational Cohort Study (Ballering, August 2022)
- Rates and Factors Associated With Documentation of Diagnostic Codes for Long COVID in the National Veterans Affairs Health Care System (Ioannou, July 2022)
- Short-Term and Long-Term Rates of Postacute Sequelae of SARS-CoV-2 Infection (Groff, October 2021)
- Long-Term Symptoms Among Adults Tested for SARS-CoV-2 – United States, January 2020-April 2021 (Wanga, September 2021)
- Long COVID Symptoms in SARS-CoV-2-Positive Children Aged 0–14 Years and Matched Controls in Denmark (LongCOVIDKidsDK): A National, Cross-Sectional Study (Berg, September 2022)
- Post–COVID-19 Symptoms and Conditions Among Children and Adolescents — United States, March 1, 2020–January 31, 2022 (Kompaniyets, August 2022)
- Post–COVID-19 Conditions Among Children 90 Days After SARS-CoV-2 Infection (Funk, July 2022)
- Long-COVID in Children and Adolescents: A Systematic Review and Meta-Analyses (Lopez-Leon, June 2022)
- Multidisciplinary Collaborative Consensus Guidance Statement on the Assessment and Treatment of Fatigue in Postacute Sequelae of SARS-CoV-2 Infection (PASC) Patients (Herrera, September 2021)
- Managing the Long Term Effects of COVID-19: Summary of NICE, SIGN, and RCGP Rapid Guideline (Shah, January 2021)
Impact of Therapeutics/Vaccines
- Trajectory of Long COVID Symptoms After COVID-19 Vaccination: Community Based Cohort Study (Ayoubkhani, May 2022)