With long COVID now increasingly recognised, a challenge for healthcare systems across the world is how best to manage these patients.
COVID-19 is now recognised as a multi-organ disease with a broad spectrum of manifestations. A further and important consequence of infection that is also recognised, is that for an increasing number of patients, an acute infection is associated with persistent and prolonged symptoms and this has become known as long COVID. In a comprehensive review of the available literature, a multi-disciplinary team from various centres in the US, have described the long-term sequelae on the various organ systems affected by infection with COVID-19. For the purposes of the review, the team have defined post-acute COVID-19 as persistent symptoms and/or delayed or long-term complications beyond 4 weeks from the initial onset of the acute viral symptoms. The authors have further subdivided symptoms into those present from between 4 and 12 weeks after the acute infection and cases where symptoms have persisted beyond 12 weeks and for which there is no attributable alternative diagnosis. According to the review, the epidemiology of persistent symptoms has been reported in the literature to vary considerably, ranging from 32% to 87%. One of the largest reported studies described was conducted with 1733 patients from Wuhan, China, among whom, 76% reported at least one symptom from fatigue/muscle weakness, difficulty sleeping and anxiety/depression up to six months after their initial infection. While the pathophysiology of these changes remains unclear, suggested mechanisms have included microvascular ischaemic and injury, immobility and metabolic alterations.
The post-acute COVID-19 syndrome impacts on many parts of the body including the pulmonary, haematological, endocrine, cardiovascular, neurological, renal, gastrointestinal/hepatobiliary and dermatological organ systems. In addition, a distinct, multisystem inflammatory syndrome has been described in association with COVID-19 infection that specifically affects people under 21 years of age and is characterised by fever, elevation of inflammatory markers and multiple organ dysfunction. Although some evidence has suggested that patients with skin of colour have been disproportionally affected by COVID-19, the authors note that they are few biological factors able to explain these differences and suggest that socioeconomic factors might have a more important role.
The authors welcomed the fact that there is now widespread acceptance in the medical community that symptom continuation occurs in a subset of patients after the initial infection. However, they also note that future work should focus on the identification and characterisation of key clinical, serological, imaging and epidemiological features, in order to provide a better understanding the natural history and pathophysiology of this new disease. In addition, they called for greater interdisciplinary cooperation to ensure comprehensive care for affected patients and note how it is increasingly likely that the health needs for patients with continued will become a global concern in the foreseeable future.
The authors concluded that catering for the mental and physical needs of affected individuals represents a major challenge that will require the development of scalable healthcare models for potentially several years to come.
Citation
Nalbandian A et al. Post-acute COVID-19 syndrome. Nat Med 2021 https://doi.org/10.1038/s41591-021-01283-z
