Long COVID
Long COVID or long-haul COVID is a group of health problems persisting or developing after an initial period of COVID-19 infection. Symptoms can last weeks, months or years and are often debilitating.[3] The World Health Organization defines long COVID as starting three months after the initial COVID-19 infection, but other agencies define it as starting at four weeks after the initial infection.[2]
"Post COVID" redirects here. For the South Park special, see South Park: Post Covid.Long COVID
Long-haul COVID, post-COVID-19 syndrome, post-COVID-19 condition, post-acute sequelae of COVID-19 (PASC), chronic COVID syndrome[1]
Highly varied, including post-exertional malaise (symptoms worsen with effort), fatigue, muscle pain, shortness of breath, chest pain and cognitive dysfunction ("brain fog")[2]
Weeks to years, possibly lifelong[3]
COVID-19 infection
50–70% of hospitalised COVID-19 cases, 10–30% of non-hospitalised cases, and 10–12% of vaccinated cases[3]
Long COVID is characterised by a large number of symptoms that sometimes disappear and then reappear. Commonly reported symptoms of long COVID are fatigue, memory problems, shortness of breath, and sleep disorder.[5][6][7] Several other symptoms, including headaches, mental health issues, loss of smell or taste, muscle weakness, fever, and cognitive dysfunction may also present.[5][7] Symptoms often get worse after mental or physical effort, a process called post-exertional malaise.[5] There is a large overlap in symptoms with myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS).[2]
The causes of long COVID are not yet fully understood. Hypotheses include lasting damage to organs and blood vessels, problems with blood clotting, neurological dysfunction, persistent virus or a reactivation of latent viruses and autoimmunity.[3] Diagnosis of long COVID is based on (suspected or confirmed) COVID-19 infection or symptoms—and by excluding alternative diagnoses.[8][9]
Estimates of the prevalence of long COVID vary based on definition, population studied, time period studied, and methodology, generally ranging between 5% and 50%.[10] Prevalence is less after vaccination.[11] Risk factors are higher age, female sex, having asthma, and a more severe initial COVID-19 infection.[4] As of 2023, there are no validated effective treatments.[3][5] Management of long COVID depends on symptoms. Rest is recommended for fatigue and pacing for post-exertional malaise. People with severe symptoms or those who were in intensive care may require care from a team of specialists.[12] Most people with symptoms at 4 weeks recover by 12 weeks. Recovery is slower (or plateaus) for those still ill at 12 weeks.[12] For a subset of people, for instance those meeting the criteria for ME/CFS, symptoms are expected to be lifelong.[3]
Diagnosis[edit]
There are no standardised tests to determine if symptoms persisting after COVID-19 infection are due to long COVID.[5][9] Diagnosis is based on a history of suspected or confirmed COVID-19 symptoms, and by considering and ruling out alternative diagnoses.[8][9] Diagnosis of long COVID can be challenging because of the wide range of symptoms people with long COVID may display.[9]
Early diagnostic criteria of long COVID required a laboratory-confirmed COVID-19 infection, but current criteria do not require this anymore, given that people may not get tested during the acute infection.[9] For instance, people who develop long COVID after asymptomatic infection would have little reason to get tested.[8] Furthermore, tests for COVID are not foolproof, and can come back negative.[8] False negatives are more common for children, women and people with a low viral load.[3]
There are diagnostic tools available for some elements of long COVID, such as the tilt table test for POTS and MRI scans to test for cardiovascular impairment. Routine tests offered in standard care often come back normal.[3]
Prevention[edit]
Preventing a COVID-19 infection is the most effective way to prevent long COVID, for instance by improving ventilation, avoiding contact with people who test positive for COVID, washing hands, and wearing a properly-fitted N95 mask.[42] Treatment during the acute phase may also reduce the risk of long COVID.[5]
COVID-19 vaccination reduces the risk of long COVID, but by how much is unclear, as the available studies differ widely and are of limited quality.[11] One complication is that healthy people more often opt to get vaccinated, which makes it more difficult to draw conclusions on the effect of vaccination.[43] A 2023 review found that three doses of a COVID-19 vaccine offer 69% effectiveness against long COVID, while two doses had 37% efficacy, for those who had not been infected with COVID-19 before.[44][45]
Clinical care[edit]
As of 2023 there are no established effective treatments for long COVID,[3] however several countries and medical organizations have produced guidelines on long COVID for clinicians and the public.[5][46][47]
People with long COVID may need care within several clinical disciplines for long-term monitoring or intervention of ongoing symptoms, and to implement social services, physical therapy, or mental health care.[47] In some countries, such as the UK and Germany, specialised long COVID outpatient clinics have been established to assess individual cases for the extent of surveillance and treatment needed.[48] Two reviews indicated that primary physicians should provide the first assessment of people with long COVID symptoms, leading to specialist referrals for more complex long COVID symptoms.[47][48]
Management of long COVID depends on symptoms.[5] Rest, planning and prioritising are advised for people with fatigue. People who get post-exertional malaise may benefit from activity management with pacing. People with allergic-type symptoms, such as skin rashes, may benefit from antihistamines.[12] Those with autonomic dysfunction may benefit from increased intake of fluids, electrolytes and compression garments.[12]
Long-term follow-up of people with long COVID involves outcome reports from the people themselves to assess the impact on their quality of life, especially for those who were not hospitalised and receiving regular clinical follow-up.[47][48] Digital technologies, such as videoconferencing, are being implemented between primary care physicians and people with long COVID as part of long-term monitoring.[47]
Prognosis[edit]
Around two in three with symptoms at four weeks are expected to recover fully by week twelve.[12] However, the prognosis varies by person, and some may find symptoms worsen within the first three months.[8] Recovery after twelve weeks is variable: some people plateau, whilst others see a slow recovery.[12]
The prognosis also varies by symptom: neurological symptoms may have a delayed onset, and some get worse over time. Symptoms of the gut and lungs are more likely to reduce over time. Pain in muscles and joints seems worse at 2 years than at 1 year after infection. If people meet the diagnostic criteria for ME/CFS or for dysautonomia, their symptoms are likely to be lifelong.[3]
Society and culture[edit]
Patient community and activism[edit]
Early in the pandemic, official guidance made a distinction between those with mild illness who did not require hospitalisation, and those with severe illness which did require hospitalisation. The typical recovery time for those with mild illness was said to be around two weeks[58] and media attention was mostly focused on those with a severe infection. Patients with long-lasting systems after a mild infection started to describe their symptoms on Twitter and blogs,[59] challenging official assumptions.[60]
The term long COVID was reportedly first used in May 2020 as a hashtag on Twitter by Elisa Perego, a health and disability researcher at University College London.[13][60] A month later, #LongCovid became a popular hashtag, alongside hashtags from non-English budding communities (for instance, #AprèsJ20 in French, and #koronaoire in Finnish).[60]
Experiences shared online filled a gap in knowledge in how the media talked about the pandemic.[59] Via the media, the knowledge reached governments and health officials, making long COVID "the first illness created through patients finding one another on Twitter".[60]
Some people experiencing long COVID have formed community care networks and support groups on social media websites.[48][61] Internationally, there are several long COVID advocacy groups.[47][62][63][64] Clinical advice on self-management and online healthcare programs are used to support people with long COVID.[48]
Stigma and discrimination[edit]
Many people with long COVID have difficulty accessing appropriate healthcare. The severity of their symptoms may be disbelieved, they may be subject to unsympathetic care, and their symptoms may not be investigated properly or may be falsely attributed to anxiety.[65][47] People with long COVID may be misdiagnosed with mental disorders. Anxiety and depression questionnaires not designed for people with medical conditions can contribute to this; for example, a questionnaire may assume fatigue is due to depression or that palpitations are due to anxiety, even if explained by another condition like ME/CFS or POTS.[3]
[edit]
The impact of long COVID on people's ability to work is large. Estimates vary on how many people are out of work, or work reduced hours because of long COVID. For those with mild or moderate disease, between 12% and 23% had had long periods of absence or remained absent from work at 3 to 7 months. The share of people working adjusted hours or tasks after mild or moderate COVID, was around 8% to 45% after three to eight months.[66] The percentage of people returning to work after hospitalisation was lower.[66] Return to work after hospitalisation differed by country. In China and the US a higher percentage went back to work. In the US this could be partially explained by a lack of paid sick leave for some workers.[67] The Institute for Fiscal Studies studied labour impacts of long COVID in the UK in 2021. They concluded that of people who worked before contracting long COVID, one in ten had stopped working. Most of them were on sick leave rather than unemployed.[68]
Research[edit]
As long COVID is a novel condition, open questions abound. Research is ongoing in many areas, including developing more accurate diagnostic criteria, refining estimates of its likelihood, identifying risk factors, gathering data for its impact on daily life, discovering which populations face barriers to adequate care, and learning how much protection vaccination provides.[69][70]
Many experimental and repurposed drugs are being investigated as possible treatments for different aspects of long COVID.[3][71] These include the anti-inflammatory colchicine, the anticoagulant rivaroxaban, the antihistamines famotidine and loratadine, various immune-modulating drugs, and the experimental aptamer compound BC-007.[2][3]
In 2021, the US National Institutes of Health started funding the RECOVER Initiative, backed by $1.15 billion over four years,[72] to identify the causes, prevention and treatment of long COVID.[29] In 2023, the Office of Long COVID Research and Practice was created to coordinate research across US government agencies.[73] At the same time, RECOVER announced which clinical trials it will fund: these include a trial of Paxlovid against potential persistent infection, one for sleep disorder, one for cognitive impairment and one for problems with the autonomic nervous system.[74]
In a 2023 survey of 3,700 people with long COVID, fatigue was the symptom most closely associated with poor everyday functioning, while quality of life, depression and brain fog also occurred.[75] Some 20% of people with long COVID were unable to work.[75][76]