Long COVID

Long COVID, long covid, and post-acute COVID-19 are terms used to describe a group of long term health problems that are found in a significant minority of people who were infected with the COVID-19 and remain ill after a number of weeks or months.

In February 2020, the World Health Organization stated that the expected recovery time from COVID-19 was 2 weeks for mild cases, and between three and six weeks for severe cases; follow-up studies then identified a significant number of COVID-19 patients had remained ill much longer than this: those with long COVID.

A similar phenomenon to long COVID occurred after the 2003 outbreak of the similar SARS coronavirus, which lead to a post-SARS syndrome being proposed that included chronic widespread musculoskeletal pain, fatigue, depression and disordered sleep. Another study found a subgroup SARS survivors developed chronic fatigue syndrome immediately after SARS.

Long-haulers
A "long-hauler" is someone who became ill with confirmed or suspected COVID-19, who has not recovered many weeks or months later after first becoming ill.

What is long COVID
Long COVID appears to be a multisystem disease, and may occur after any severity of COVID-19, including after relatively mild cases.

Signs and symptoms
Patient surveys have reported that the following symptoms commonly occur in long COVID. Other reported symptoms include:
 * Fatigue, which may be profound (very severe)
 * Muscle pain or body aches
 * Breathlessness
 * Concentration problems
 * Inability to exercise/exercise intolerance
 * Headache
 * Insomnia or problems sleeping
 * Heavy chest, a feeling of pressure on the chest, or chest pain
 * Anxiety
 * Memory problems
 * Skin rashes
 * Heart palpitations
 * Fever
 * Diarrhea
 * Dizziness
 * The sensation of pins and needles
 * Cough
 * Joint pain

Research
Surveys of data collected and published by long haulers using social media were the first evidence of what symptoms and health problems were caused by long COVID. Later academic studies confirmed many of the initial long hauler survey findings, although many only involved patients discharged from hospital, patients who had been able to access early testing and tested positive, or patients who had sought medical care in a particular location. People with mild COVID-19 symptoms, leaving people denied testing and those who may have had false negative test results and people who tested positive but were asymptomatic underrepresented in long COVID research.

Pacing
Pacing is a method of activity management which aims to adapt everday activities in order to avoid relapses or increased symptoms.

Exercise therapy
ME/CFS patient groups have raised concerns about the use of graded exercise therapy (GET) in long COVID patients and a similar warning has been issued by NICE in the UK. Graded exercise therapy, which is sometimes incorrectly referred to as "activity management" involves patients initially reducing their activity levels to a level that prevents regular crashes, and then typically increasing activity by 10% each week regardless of any increased symptoms or worsening illness. In graded exercise patients are told to ignore deterioration or increased symptoms and "push through" them.

Theory and evidence
In graded exercise therapy patients are told that their symptoms are caused only by inactivity and other "bad habits" rather than an underlying illness. These assumptions have very weak evidence, and significant evidence exists of underlying illness in ME/CFS; there is a lack of research about exercise therapy for long COVID illness but some symptoms are inconsistent with this "deconditioning" assumption and some research has found physical abnormalities in some patients weeks or month after infection. Surveys of ME/CFS patients have consistently shown that large numbers of patients deteriorate as a result of graded exercise therapy, and a significant number become severely ill and never return to the level of functioning they had before the treatment.

ME/CFS
Postviral fatigue syndrome is one of the previous names used for Myalgic Encephalomyelitis (ME), sometimes known as Chronic Fatigue Syndrome (CFS), and it commonly begins immediately after events such as a virus, bacterial or other infection. ME/CFS is not normally diagnosed until symptoms have persisted for six months or more, and tests must be run to exclude other possible causes of the symptoms. Some contagious diseases including Epstein-Barr virus, certain enteroviruses, and the SARS virus, have caused outbreaks of ME/CFS. It is not yet known how likely it is for ME/CFS to begin immediately after COVID-19 illness, although around 10% people with certain viruses are known to develop ME/CFS, and according to the BMJ around 10% of people with COVID-19 have developed prolonged illness.

Patient surveys
Not peer reviewed
 * May 2020, What Does COVID-19 Recovery Actually Look Like? An Analysis of the Prolonged COVID-19 Symptoms Survey by Patient-Led Research Team - by Body Politic
 * Data collected: Apr 21 - May 2 2020. Respondents: 640


 * Jul 2020, COVID-19 “Long Hauler” Symptoms Survey Report - with Survivor Corps
 * Data collected: Jul 25, 2020. Respondents: 1,567+

Notable studies

 * Aug 14, 2020 (pre-print), Patient outcomes after hospitalisation with COVID-19 and implications for follow-up; results from a prospective UK cohort - (Full text) - from the DISCOVER project
 * Aug 11, 2020, Management of post-acute covid-19 in primary care - (Full text)
 * Jul 24, 2020, Outcomes of Cardiovascular Magnetic Resonance Imaging in Patients Recently Recovered From Coronavirus Disease 2019 (COVID-19) (Full text)

Presentations, interviews and videos

 * Aug 2020, Will Covid-19 lead to ME/CFS in some people? - presentation - Dr Anthony Komaroff
 * Jul 2020, Message in a Bottle video - LongCovidSOS

Letters and blogs

 * Sep 2020, Understanding Long Covid, A Shortcut to Solving ME/CFS? Simon McGrath
 * Jul 2020, Letter re Covid-19 Management and Exercise Caution - Forward-ME

National and international health bodies

 * NICE cautions against using graded exercise therapy for patients recovering from COVID-19

News articles

 * Oct 2020, Long Covid: the evidence of lingering heart damage - The Observer
 * Sep 2020, Coronavirus patient unable to work six months on - BBC News
 * Aug 2020, The Most Common Long-Term Symptoms Of Covid-19 - HuffPost UK

Learn more

 * COVID-19 Long Term Health Effects
 * Infographic: "Long covid" in primary care - BMJ journal
 * List of long COVID studies (draft) - #MEAction