Long COVID

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For COVID-19 main page, click here For COVID-19 frequently asked inpatient questions, click here For COVID-19 frequently asked outpatient questions, click here

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Mitra Chitsazan, M.D.[2] Edzel Lorraine Co, DMD, MD[3]

Synonyms and keywords: Long COVID Syndrome, long COVID, long-haul COVID, post-COVID-19 condition, post-COVID-19 syndrome, post-acute sequelae of COVID-19 (PASC), chronic COVID syndrome (CCS), Long-hauler COVID-19, Long-tail COVID, Long-haulers, Post-acute COVID-19 syndrome, Acute post-COVID symptoms, Long post-COVID symptoms, Persistent post-COVID symptoms, Post-acute COVID-19, On-going symptomatic COVID-19, Chronic COVID-19

Overview

Shortly after the COVID-19 pandemic onset, emerging studies showed that a considerable proportion of patients with COVID-19 might exhibit sustained postinfection sequelae. This condition has been defined by a variety of names, including long COVID or long-haul COVID, and post-COVID-19 condition. The absence of a universally standardized terminology has made characterization of the epidemiology, risk factors, clinical characteristics, and potential treatments options difficult. Symptoms may occur as an unpredictable combination of respiratory, cardiovascular, urological, neurological, and/or gastrointestinal manifestations. However, the most common symptoms include fatigue, dyspnea, and cognitive dysfunction (known as brain fog by the patients). Symptoms may begin following initial recovery from an acute COVID-19 episode or may persist from the initial acute episode. Symptoms might also fluctuate or relapse over time.

Historical Perspective

Definition

  • On October 6, 2021, World Health Organization (WHO) released a clinical case definition of the post-COVID-19 condition through a robust, protocol-based methodology (Delphi consensus), which engaged a diverse group of representative patients, patient-researchers, external experts, WHO staff, and other stakeholders from multiple geographies. [3] It was acknowledged that this definition may change with emerging new evidence and continuously evolving our understanding of the consequences of COVID-19.
  • According to WHO clinical case definition, the post-COVID-19 condition is defined as: [3]
Source Terms Definition
WHO [3] Post-COVID-19 condition
CDC [4] Long COVID
  • While most persons with COVID-19 recover and return to normal health, some patients can have symptoms that can last for weeks or even months after recovery from acute illness.
  • Even people who are not hospitalized and who have a mild illness can experience persistent or late symptoms."
Nature [5] Post-acute COVID-19
Lancet [6] Long COVID
  • Multiorgan symptoms after COVID-19 are being reported by increasing numbers of patients.
  • They range from cough and shortness of breath to fatigue, headache, palpitations, chest pain, joint pain, physical limitations, depression, and insomnia, and affect people of varying ages.
  • At the Lancet–Chinese Academy of Medical Sciences conference on 23 November 2020, Bin Cao presented data (in press at the Lancet) on the long-term consequences of COVID-19 for patients in Wuhan and warned that dysfunctions and complications could persist in some discharged patients for at least 6 months.
  • So-called long COVID is a burgeoning health concern and action is needed now to address it.
Nice [7] Long COVID
Scientific American [8] Long Haul COVID
  • Individuals whose symptoms persist or develop outside the initial viral infection, but the duration and pathogenesis are unknown.
Royal Society [9] Long COVID
Haute Autorité de santé, France [10] Long COVID
  • Three criteria:
    • Having presented with symptomatic form of COVID-19
    • Presenting with one or more initial symptoms 4 weeks after the start of the disease
    • None of these symptoms can be explained by another diagnosis

Classification

There is no established system for the classification of long COVID.

Pathophysiology

The exact pathogenesis of long COVID is not fully understood. A controlled study found no unique abnormalities[11] However, a number of putative pathophysiologic mechanisms have been suggested.

Cytokines and Biomarkers

Epidemiology and Demographics

A cohort study found the COVID alpha variant found[39]:

  • "Persistent symptoms in COVID-19-positive participants at 90-150 days after COVID-19 compared with before COVID-19 and compared with matched controls included chest pain, difficulties with breathing, pain when breathing, painful muscles, ageusia or anosmia, tingling extremities, lump in throat, feeling hot and cold alternately, heavy arms or legs, and general tiredness."
  • "In 12·7% of patients, these symptoms could be attributed to COVID-19, as 381 (21·4%) of 1782 COVID-19-positive participants versus 361 (8·7%) of 4130 COVID-19-negative controls had at least one of these core symptoms substantially increased to at least moderate severity at 90-150 days after COVID-19 diagnosis or matched timepoint."

Risk Factors

Screening

There is insufficient evidence to recommend routine screening for long COVID.

Natural History, Complications, and Prognosis

  • The natural history, clinical course, long-term complications, and prognosis of long COVID-19 are still not completely understood.
  • Manifestations of the post-COVID-19 condition vary considerably in terms of organ involvement and severity of symptoms; however, they generally impact the everyday functioning of affected patients. [3]
  • Symptoms might newly develop following initial recovery from an acute COVID-19 illness or occur as a persist from the initial episode. [3]
  • Symptoms might also fluctuate or relapse over time. [3]

Diagnosis

Diagnostic Study of Choice

History and Symptoms

Long COVID can involve almost every organ. The most common symptoms of long COVID include: [3] [37] [41] [42]

Physical Examination

Laboratory Findings

There are no diagnostic laboratory findings associated with long COVID. Symptoms do not correlate with the serology of SARS-CoV-2.

Electrocardiography

In patients with cardiopulmonary symptoms, an ECG may be needed.

X-ray

A chest x-ray may be helpful in the diagnosis of pulmonary complications of COVID-19 such as lung damage (ie, ground glass opacities, consolidation, interlobular septal thickening) and pleural effusion.

Echocardiography or Ultrasound

In selected patients with cardiopulmonary symptoms, echocardiography may be necessary.

CT scan

In patients with cardiopulmonary symptoms, a chest CT scan may be needed.

MRI

There are no MRI findings associated with long COVID. However, a cardiac MRI may be helpful in the diagnosis of myocarditis in COVID-19 patients.

Other Imaging Findings

There are no other imaging findings associated with long COVID.

Other Diagnostic Studies

In selected patients with cardiopulmonary symptoms, Holter monitoring, cardiopulmonary exercise testing (CPET), and pulmonary function tests may be necessary.

Treatment

Due to the diversity of symptoms and their severity, the mainstay of long COVID treatment is multidisciplinary and supportive. The management should focus on supporting self-management and individualized rehabilitation. [43] [44]

Medical Therapy

  • Alopecia
    • There is no specific therapy for alopecia in COVID-19 patients, and it should be managed similarly to non-COVID-19 patients.
    • In patients with concomitant malnutrition, nutritional deficiencies should be corrected.

Primary Prevention

The most effective measure to prevent the post-COVID-19 condition is to prevent COVID-19. These primary prevention strategies include:

Secondary Prevention

There are no established measures for the secondary prevention of long COVID.

References

  1. Callard F, Perego E (2021). "How and why patients made Long Covid". Soc Sci Med. 268: 113426. doi:10.1016/j.socscimed.2020.113426. PMC 7539940 Check |pmc= value (help). PMID 33199035 Check |pmid= value (help).
  2. "Emergency use ICD codes for COVID-19 disease outbreak".
  3. 3.0 3.1 3.2 3.3 3.4 3.5 3.6 3.7 Soriano JB, Murthy S, Marshall JC, Relan P, Diaz JV, WHO Clinical Case Definition Working Group on Post-COVID-19 Condition (2021). "A clinical case definition of post-COVID-19 condition by a Delphi consensus". Lancet Infect Dis. doi:10.1016/S1473-3099(21)00703-9. PMC 8691845 Check |pmc= value (help). PMID 34951953 Check |pmid= value (help).
  4. "Post-COVID Conditions | CDC".
  5. Nalbandian A, Sehgal K, Gupta A, Madhavan MV, McGroder C, Stevens JS; et al. (2021). "Post-acute COVID-19 syndrome". Nat Med. 27 (4): 601–615. doi:10.1038/s41591-021-01283-z. PMC 8893149 Check |pmc= value (help). PMID 33753937 Check |pmid= value (help).
  6. "Facing up to long COVID". Lancet. 396 (10266): 1861. 2020. doi:10.1016/S0140-6736(20)32662-3. PMC 7834723 Check |pmc= value (help). PMID 33308453 PMID: 33308453 Check |pmid= value (help).
  7. "Overview | COVID-19 rapid guideline: managing the long-term effects of COVID-19 | Guidance | NICE".
  8. "The Problem of 'Long Haul' COVID - Scientific American".
  9. "royalsociety.org" (PDF).
  10. "Épidémie de Coronavirus (Covid-19) -Covid long : les recommandations de la Haute Autorité de santé | service-public.fr".
  11. Sneller MC, Liang CJ, Marques AR, Chung JY, Shanbhag SM, Fontana JR, Raza H, Okeke O, Dewar RL, Higgins BP, Tolstenko K, Kwan RW, Gittens KR, Seamon CA, McCormack G, Shaw JS, Okpali GM, Law M, Trihemasava K, Kennedy BD, Shi V, Justement JS, Buckner CM, Blazkova J, Moir S, Chun TW, Lane HC. A Longitudinal Study of COVID-19 Sequelae and Immunity: Baseline Findings. Ann Intern Med. 2022 PMID: 35605238
  12. Truffaut L, Demey L, Bruyneel AV, Roman A, Alard S, De Vos N; et al. (2021). "Post-discharge critical COVID-19 lung function related to severity of radiologic lung involvement at admission". Respir Res. 22 (1): 29. doi:10.1186/s12931-021-01625-y. PMC 7819622 Check |pmc= value (help). PMID 33478527 PMID: 33478527 Check |pmid= value (help).
  13. Han X, Fan Y, Alwalid O, Li N, Jia X, Yuan M; et al. (2021). "Six-month Follow-up Chest CT Findings after Severe COVID-19 Pneumonia". Radiology. 299 (1): E177–E186. doi:10.1148/radiol.2021203153. PMC 7841877 Check |pmc= value (help). PMID 33497317 PMID: 33497317 Check |pmid= value (help).
  14. Bellan M, Soddu D, Balbo PE, Baricich A, Zeppegno P, Avanzi GC; et al. (2021). "Respiratory and Psychophysical Sequelae Among Patients With COVID-19 Four Months After Hospital Discharge". JAMA Netw Open. 4 (1): e2036142. doi:10.1001/jamanetworkopen.2020.36142. PMC 7841464 Check |pmc= value (help). PMID 33502487 PMID: 33502487 Check |pmid= value (help).
  15. Liu D, Zhang W, Pan F, Li L, Yang L, Zheng D; et al. (2020). "The pulmonary sequalae in discharged patients with COVID-19: a short-term observational study". Respir Res. 21 (1): 125. doi:10.1186/s12931-020-01385-1. PMC 7245637 Check |pmc= value (help). PMID 32448391 PMID: 32448391 Check |pmid= value (help).
  16. Marvisi M, Ferrozzi F, Balzarini L, Mancini C, Ramponi S, Uccelli M (2020). "First report on clinical and radiological features of COVID-19 pneumonitis in a Caucasian population: Factors predicting fibrotic evolution". Int J Infect Dis. 99: 485–488. doi:10.1016/j.ijid.2020.08.054. PMC 7443096 Check |pmc= value (help). PMID 32841688 PMID: 32841688 Check |pmid= value (help).
  17. Wei J, Yang H, Lei P, Fan B, Qiu Y, Zeng B; et al. (2020). "Analysis of thin-section CT in patients with coronavirus disease (COVID-19) after hospital discharge". J Xray Sci Technol. 28 (3): 383–389. doi:10.3233/XST-200685. PMC 7369060 Check |pmc= value (help). PMID 32474479 PMID: 32474479 Check |pmid= value (help).
  18. 18.0 18.1 Maksoud R, du Preez S, Eaton-Fitch N, Thapaliya K, Barnden L, Cabanas H | display-authors=etal (2020) A systematic review of neurological impairments in myalgic encephalomyelitis/ chronic fatigue syndrome using neuroimaging techniques. PLoS One 15 (4):e0232475. DOI:10.1371/journal.pone.0232475 PMID: 32353033
  19. Rubin R (2020). "As Their Numbers Grow, COVID-19 "Long Haulers" Stump Experts". JAMA. 324 (14): 1381–1383. doi:10.1001/jama.2020.17709. PMID 32965460 Check |pmid= value (help).
  20. 20.0 20.1 Dani M, Dirksen A, Taraborrelli P, Torocastro M, Panagopoulos D, Sutton R; et al. (2021). "Autonomic dysfunction in 'long COVID': rationale, physiology and management strategies". Clin Med (Lond). 21 (1): e63–e67. doi:10.7861/clinmed.2020-0896. PMC 7850225 Check |pmc= value (help). PMID 33243837 Check |pmid= value (help).
  21. Komaroff AL, Bateman L (2020). "Will COVID-19 Lead to Myalgic Encephalomyelitis/Chronic Fatigue Syndrome?". Front Med (Lausanne). 7: 606824. doi:10.3389/fmed.2020.606824. PMC 7848220 Check |pmc= value (help). PMID 33537329 Check |pmid= value (help).
  22. Jamal SM, Landers DB, Hollenberg SM, Turi ZG, Glotzer TV, Tancredi J, Parrillo JE. Prospective Evaluation of Autonomic Dysfunction in Post-Acute Sequela of COVID-19. J Am Coll Cardiol. 2022 Jun 14;79(23):2325-2330. doi: 10.1016/j.jacc.2022.03.357. Epub 2022 Apr 2. PMID: <a href="http://pubmed.gov/35381331">35381331</a>
  23. Motiejunaite J, Balagny P, Arnoult F, Mangin L, Bancal C, d'Ortho MP; et al. (2020). "Hyperventilation: A Possible Explanation for Long-Lasting Exercise Intolerance in Mild COVID-19 Survivors?". Front Physiol. 11: 614590. doi:10.3389/fphys.2020.614590. PMC 7849606 Check |pmc= value (help). PMID 33536937 Check |pmid= value (help).
  24. Yong SJ (2021). "Persistent Brainstem Dysfunction in Long-COVID: A Hypothesis". ACS Chem Neurosci. 12 (4): 573–580. doi:10.1021/acschemneuro.0c00793. PMC 7874499 Check |pmc= value (help). PMID 33538586 Check |pmid= value (help).
  25. Zang R, Gomez Castro MF, McCune BT, Zeng Q, Rothlauf PW, Sonnek NM; et al. (2020). "TMPRSS2 and TMPRSS4 promote SARS-CoV-2 infection of human small intestinal enterocytes". Sci Immunol. 5 (47). doi:10.1126/sciimmunol.abc3582. PMC 7285829 Check |pmc= value (help). PMID 32404436 Check |pmid= value (help).
  26. Xiao F, Tang M, Zheng X, Liu Y, Li X, Shan H (2020). "Evidence for Gastrointestinal Infection of SARS-CoV-2". Gastroenterology. 158 (6): 1831–1833.e3. doi:10.1053/j.gastro.2020.02.055. PMC 7130181 Check |pmc= value (help). PMID 32142773 Check |pmid= value (help).
  27. Gaebler C, Wang Z, Lorenzi JCC, Muecksch F, Finkin S, Tokuyama M; et al. (2021). "Evolution of antibody immunity to SARS-CoV-2". Nature. 591 (7851): 639–644. doi:10.1038/s41586-021-03207-w. PMC 8221082 Check |pmc= value (help). PMID 33461210 Check |pmid= value (help).
  28. Lamers MM, Beumer J, van der Vaart J, Knoops K, Puschhof J, Breugem TI; et al. (2020). "SARS-CoV-2 productively infects human gut enterocytes". Science. 369 (6499): 50–54. doi:10.1126/science.abc1669. PMC 7199907 Check |pmc= value (help). PMID 32358202 Check |pmid= value (help).
  29. Cheung KS, Hung IFN, Chan PPY, Lung KC, Tso E, Liu R; et al. (2020). "Gastrointestinal Manifestations of SARS-CoV-2 Infection and Virus Load in Fecal Samples From a Hong Kong Cohort: Systematic Review and Meta-analysis". Gastroenterology. 159 (1): 81–95. doi:10.1053/j.gastro.2020.03.065. PMC 7194936 Check |pmc= value (help). PMID 32251668 Check |pmid= value (help).
  30. Mao R, Qiu Y, He JS, Tan JY, Li XH, Liang J; et al. (2020). "Manifestations and prognosis of gastrointestinal and liver involvement in patients with COVID-19: a systematic review and meta-analysis". Lancet Gastroenterol Hepatol. 5 (7): 667–678. doi:10.1016/S2468-1253(20)30126-6. PMC 7217643 Check |pmc= value (help). PMID 32405603 Check |pmid= value (help).
  31. Tavakolpour S, Rakhshandehroo T, Wei EX, Rashidian M (2020). "Lymphopenia during the COVID-19 infection: What it shows and what can be learned". Immunol Lett. 225: 31–32. doi:10.1016/j.imlet.2020.06.013. PMC 7305732 Check |pmc= value (help). PMID 32569607 Check |pmid= value (help).
  32. Karlsson AC, Humbert M, Buggert M (2020). "The known unknowns of T cell immunity to COVID-19". Sci Immunol. 5 (53). doi:10.1126/sciimmunol.abe8063. PMID 33208380 Check |pmid= value (help).
  33. Singh I, Joseph P, Heerdt PM, Cullinan M, Lutchmansingh DD, Gulati M; et al. (2022). "Persistent Exertional Intolerance After COVID-19: Insights From Invasive Cardiopulmonary Exercise Testing". Chest. 161 (1): 54–63. doi:10.1016/j.chest.2021.08.010. PMC 8354807 Check |pmc= value (help). PMID 34389297 Check |pmid= value (help).
  34. Queiroz MAF, Neves PFMD, Lima SS, Lopes JDC, Torres MKDS, Vallinoto IMVC; et al. (2022). "Cytokine Profiles Associated With Acute COVID-19 and Long COVID-19 Syndrome". Front Cell Infect Microbiol. 12: 922422. doi:10.3389/fcimb.2022.922422. PMC 9279918 Check |pmc= value (help). PMID 35846757 Check |pmid= value (help).
  35. Wais T, Hasan M, Rai V, Agrawal DK (2022). "Gut-brain communication in COVID-19: molecular mechanisms, mediators, biomarkers, and therapeutics". Expert Rev Clin Immunol. 18 (9): 947–960. doi:10.1080/1744666X.2022.2105697. PMC 9388545 Check |pmc= value (help). PMID 35868344 Check |pmid= value (help).
  36. Vianello A, Guarnieri G, Braccioni F, Lococo S, Molena B, Cecchetto A; et al. (2022). "The pathogenesis, epidemiology and biomarkers of susceptibility of pulmonary fibrosis in COVID-19 survivors". Clin Chem Lab Med. 60 (3): 307–316. doi:10.1515/cclm-2021-1021. PMID 34783228 Check |pmid= value (help).
  37. 37.0 37.1 37.2 Lopez-Leon S, Wegman-Ostrosky T, Perelman C, Sepulveda R, Rebolledo PA, Cuapio A; et al. (2021). "More than 50 long-term effects of COVID-19: a systematic review and meta-analysis". Sci Rep. 11 (1): 16144. doi:10.1038/s41598-021-95565-8. PMC 8352980 Check |pmc= value (help). PMID 34373540 Check |pmid= value (help). Review in: Ann Intern Med. 2022 Jan;175(1):JC10
  38. 38.0 38.1 Sudre CH, Murray B, Varsavsky T, Graham MS, Penfold RS, Bowyer RC; et al. (2021). "Attributes and predictors of long COVID". Nat Med. 27 (4): 626–631. doi:10.1038/s41591-021-01292-y. PMC 7611399 Check |pmc= value (help). PMID 33692530 Check |pmid= value (help).
  39. Ballering AV, van Zon SKR, Olde Hartman TC, Rosmalen JGM, Lifelines Corona Research Initiative (2022) Persistence of somatic symptoms after COVID-19 in the Netherlands: an observational cohort study. Lancet 400 (10350):452-461. DOI:10.1016/S0140-6736(22)01214-4 PMID: 35934007
  40. Ayoubkhani D, Khunti K, Nafilyan V, Maddox T, Humberstone B, Diamond I; et al. (2021). "Post-covid syndrome in individuals admitted to hospital with covid-19: retrospective cohort study". BMJ. 372: n693. doi:10.1136/bmj.n693. PMC 8010267 Check |pmc= value (help). PMID 33789877 Check |pmid= value (help).
  41. Cares-Marambio K, Montenegro-Jiménez Y, Torres-Castro R, Vera-Uribe R, Torralba Y, Alsina-Restoy X; et al. (2021). "Prevalence of potential respiratory symptoms in survivors of hospital admission after coronavirus disease 2019 (COVID-19): A systematic review and meta-analysis". Chron Respir Dis. 18: 14799731211002240. doi:10.1177/14799731211002240. PMC 7975482 Check |pmc= value (help). PMID 33729021 Check |pmid= value (help).
  42. Shah W, Hillman T, Playford ED, Hishmeh L (2021). "Managing the long term effects of covid-19: summary of NICE, SIGN, and RCGP rapid guideline". BMJ. 372: n136. doi:10.1136/bmj.n136. PMID 33483331 Check |pmid= value (help).
  43. Greenhalgh T, Knight M, A'Court C, Buxton M, Husain L (2020). "Management of post-acute covid-19 in primary care". BMJ. 370: m3026. doi:10.1136/bmj.m3026. PMID 32784198 Check |pmid= value (help).
  44. Herrera JE, Niehaus WN, Whiteson J, Azola A, Baratta JM, Fleming TK; et al. (2021). "Multidisciplinary collaborative consensus guidance statement on the assessment and treatment of fatigue in postacute sequelae of SARS-CoV-2 infection (PASC) patients". PM R. 13 (9): 1027–1043. doi:10.1002/pmrj.12684. PMC 8441628 Check |pmc= value (help). PMID 34346558 Check |pmid= value (help).
  45. Bouteleux B, Henrot P, Ernst R, Grassion L, Raherison-Semjen C, Beaufils F; et al. (2021). "Respiratory rehabilitation for Covid-19 related persistent dyspnoea: A one-year experience". Respir Med. 189: 106648. doi:10.1016/j.rmed.2021.106648. PMC 8511554 Check |pmc= value (help). PMID 34689061 Check |pmid= value (help).
  46. Hargreaves IR, Mantle D (2021). "COVID-19, Coenzyme Q10 and Selenium". Adv Exp Med Biol. 1327: 161–168. doi:10.1007/978-3-030-71697-4_13. PMID 34279837 Check |pmid= value (help).
  47. Ouyang L, Gong J (2020). "Mitochondrial-targeted ubiquinone: A potential treatment for COVID-19". Med Hypotheses. 144: 110161. doi:10.1016/j.mehy.2020.110161. PMC 7403158 Check |pmc= value (help). PMID 32795832 Check |pmid= value (help).
  48. Gvozdjakova A, Klauco F, Kucharska J, Sumbalova Z (2020). "Is mitochondrial bioenergetics and coenzyme Q10 the target of a virus causing COVID-19?". Bratisl Lek Listy. 121 (11): 775–778. doi:10.4149/BLL_2020_126. PMID 33164536 Check |pmid= value (help).
  49. 49.0 49.1 Vollbracht C, Kraft K (2021). "Feasibility of Vitamin C in the Treatment of Post Viral Fatigue with Focus on Long COVID, Based on a Systematic Review of IV Vitamin C on Fatigue". Nutrients. 13 (4). doi:10.3390/nu13041154. PMC 8066596 Check |pmc= value (help). PMID 33807280 Check |pmid= value (help).
  50. Zilberman-Itskovich S, Catalogna M, Sasson E, Elman-Shina K, Hadanny A, Lang E; et al. (2022). "Hyperbaric oxygen therapy improves neurocognitive functions and symptoms of post-COVID condition: randomized controlled trial". Sci Rep. 12 (1): 11252. doi:10.1038/s41598-022-15565-0. PMC 9276805 Check |pmc= value (help). PMID 35821512 Check |pmid= value (help).
  51. Azzolini, Elena; Levi, Riccardo; Sarti, Riccardo; Pozzi, Chiara; Mollura, Maximiliano; Mantovani, Alberto; Rescigno, Maria (1 July 2022). "Association Between BNT162b2 Vaccination and Long COVID After Infections Not Requiring Hospitalization in Health Care Workers". JAMA. doi:10.1001/jama.2022.11691. ISSN 0098-7484. PMID 35796131 Check |pmid= value (help).