Vol. 1 No. 9 (2021)
Horizon Scans

An Overview of Post–COVID-19 Condition (Long COVID)

Published September 24, 2021

Key Messages

  • Long-term symptoms after developing COVID-19, known as post–COVID-19 condition or colloquially as long COVID, is a new condition estimated to affect millions of people worldwide. While standard diagnostic criteria have not yet been developed, current estimates suggest that 21% to 23% of people suspected of having had COVID-19 may have symptoms 4 weeks after their COVID-19 infections and 14% may have symptoms 12 weeks post-infection. Among people with self-reported post–COVID-19, an estimated 40% may continue to experience symptoms for at least a year.
  • To provide health care providers and people with post–COVID-19 condition advice regarding diagnosis and treatment, guidelines have been published by the National Institute for Health and Care Excellence (NICE) and by the Centers for Disease Control and Prevention (CDC). The CDC guidelines were published more recently and refer to newer data on post–COVID-19 condition.
  • Post-COVID symptoms can affect multiple organ systems and symptoms may vary by patient characteristics such as age and sex, as well as change over time. Some people may develop more severe symptoms or have increased risk of developing other illnesses. As there are currently no known unique symptoms and no tests available to diagnose post–COVID-19 syndrome, guidelines from NICE and the CDC recommend diagnosing based on symptoms, suspected previous COVID-19 infection, and ruling out other potential causes of symptoms.
  • Current treatment recommendations focus on multidisciplinary care and personalized treatment to address the potential range of symptoms unique to each patient. Different methods of delivering treatment have been suggested and implemented around the world, including specialized post–COVID-19 clinics and integrating treatment into primary care.
  • Post–COVID-19 condition can result in a reduced ability to work or attend school, and reduced independence, which can impact quality of life. These effects may have a disproportionate impact on disadvantaged groups, which will have important implications for health equity.
  • Limited evidence on the clinical effectiveness and cost-effectiveness of therapies for post–COVID-19 condition was identified. However, many trials have been registered and are in progress to address this knowledge gap.