woman with headache wearing face mask

Long Covid

What is long covid? 

Long Covid, Covid Long Haul or PASC (Post-Acute Sequelae of SARS-Cov-2 Infection) is a syndrome observed in people who have previously tested positive for the Covid-19 infection and who, after more than 28 days, continue to experience symptoms of the disease. It is estimated that Long Covid affects 10 percent of people who contract Covid-19. As of July 2022, it was estimated that based on Worldometer calculations more than 56 million people globally were suffering varying degrees of Long Covid.  

The WHO has developed a clinical case definition of post Covid-19:  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 and 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 and 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. 

The UK’s NICE guideline provides the following case definitions for Covid-19 and Long Covid.   

Acute COVID-19 - Signs and symptoms of COVID19 for up to 4 weeks.  

Ongoing symptomatic COVID-19 - Signs and symptoms of COVID19 from 4 weeks up to 12 weeks.  

Post-COVID-19 syndrome - Signs and symptoms that develop during or after an infection consistent with COVID19, continue for more than 12 weeks and are not explained by an alternative diagnosis. It usually presents with clusters of symptoms, often overlapping, which can fluctuate and change over time and can affect any system in the body. PostCOVID19 syndrome may be considered before 12 weeks while the possibility of an alternative underlying disease is also being assessed.  

What are the symptoms? 

The symptoms of Long Covid are numerous and affect multiple systems in the body (i.e., respiratory, cardiovascular, musculoskeletal and nervous system) with the most commonly reported symptoms including:

  • fatigue 
  • shortness of breath 
  • muscle pains 
  • chest pain 
  • cognitive impairment (brain fog) 
  • headache 
  • psychological disorders such as depression and post-traumatic stress disorder. 

It is difficult to predict who will develop Long Covid. It has not only been people who were hospitalised with severe and life-threatening Covid-19 who have gone on to develop Long Covid. Individuals with reportedly mild cases of infection, who were treated at home, have also reported symptoms weeks and months later. However, what has become clear is that Long Covid has been more common in the following groups: 

  • Those with pre-existing health conditions (i.e., diabetes, asthma, hypertension) 
  • People over the age of 50 years 
  • People with a higher Body Mass Index (BMI) 
  • Women 
  • Covid-19 patients who experienced five or more symptoms in the first week of their infection. 


NHS: Long-term effects of coronavirus (long COVID)

Nice Guidance COVID-19 rapid guideline: managing the long-term effects of COVID-19 

ONS, 2021. Prevalence of ongoing symptoms following coronavirus (COVID-19) infection in the UK

SOM: COVID-19 return to work guide for managers