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Immunology of Long COVID
Long COVID refers to the long-term health and cognition effects that some people experience following infection with COVID-19. Patients have reported unrelenting fatigue, brain fog, dysautonomia, shortness of breath, and digestive problems, among over 200 symptoms — in some cases requiring frequent or even long-term hospitalization. The Iwasaki Lab is interested in exploring the biological mechanisms underlying these phenotypes — and how future research can harness this knowledge to engineer more effective and specific biomarkers for long COVID.
As researchers continue to examine how such patterns can provide information indicative of long COVID, Iwasaki proposes four possible hypotheses for the condition’s initiation and progression.
Long Covid provides an opportunity to understand
how acute infections cause chronic disease
More than 4 years into the global COVID-19 pandemic, widespread infection with severe acute respiratory syndrome coronavirus 2 (SARSCoV-2) has left millions of people around the world with Long Covid, which describes the constellation of post-acute and long-term adverse health effects caused by the infection. Evidence generated by the scientific community—with formidable contributions from patient-led research teams—has provided a thorough understanding of the epidemiology and clinical manifestations of Long Covid.
Plasma-based antigen persistence in the post-acute phase of COVID-19
Persistent symptoms among some individuals who develop COVID-19 have led to the hypothesis that SARS-CoV-2 might, in some form or location, persist for long periods following acute infection.
Studies on SARS-CoV-2 persistence to date, however, have been limited by small and non-representative study populations, short durations since acute infection, unclear documentation of vaccination and reinfection histories, and the absence of a true negative comparator group to assess assay specificity.
Blood transcriptomic analyses reveal persistent SARS-CoV-2 RNA and candidate biomarkers in post-COVID-19 condition
With an estimated 65 million individuals affected by post-COVID-19 conditions (also known as long COVID), non-invasive biomarkers are direly needed to guide clinical management. To address this pressing need, we used blood transcriptomics in a general practice-based case-control study. Individuals with long COVID were diagnosed according to WHO criteria, and validated clinical scales were used to quantify patient-reported outcomes.
Three-year outcomes of post-acute sequelae of COVID-19
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection leads to long-term health effects in nearly every organ system, collectively referred to by the patient-coined term Long Covid. Studies following infected individuals for 1 year and 2 years described risk trajectories for many conditions. Risks for some conditions abate after the first year after infection, but risks for many conditions persist at 2 years after initial infection, especially among individuals who were hospitalized for coronavirus disease 2019 (COVID-19) during the acute phase of illness.
Postacute Sequelae of SARS-CoV-2 in Children
The coronavirus disease 2019 (COVID-19) pandemic has caused significant medical, social, and economic impacts globally, both in the short and long term. Although most individuals recover within a few days or weeks from an acute infection, some experience longer lasting effects. Data regarding the postacute sequelae of severe acute respiratory syndrome coronavirus 2 infection (PASC) in children, or long COVID, are only just emerging in the literature.
Experiences of Canadians with long-term symptoms following COVID-19
The potential impact of re-infections on the risk of developing or exacerbating pre-existing long-term symptoms is important considering the endemic nature of COVID-19. However, studies providing evidence of increased risk are limited in number and generalizability.Note 18 As seen in Chart 2, Canadians reporting two known or suspected COVID-19 infections (25.4%) were 1.7 times more likely to report prolonged symptoms than those reporting only one known or suspected infection (14.6%), and those with 3 or more infections (37.9%) 2.6 times more likely.
Post-COVID-19 acute sarcopenia: physiopathology and management
In this review, we discuss the pathophysiologic and management aspects of acute sarcopenia in relation to SARS-CoV-2 infection. COVID-19 is as a multi-organ infectious disease characterized by a severe inflammatory and highly catabolic status, influencing the deep changes in the body build, especially the amount, structure, and function of skeletal muscles which would amount to acutely developed sarcopenia.
Muscle abnormalities worsen after post-exertional malaise in long COVID
A subgroup of patients infected with SARS-CoV-2 remain symptomatic over three months after infection. A distinctive symptom of patients with long COVID is post-exertional malaise, which is associated with a worsening of fatigue- and pain-related symptoms after acute mental or physical exercise, but its underlying pathophysiology is unclear. With this longitudinal case-control study (NCT05225688), we provide new insights into the pathophysiology of post-exertional malaise in patients with long COVID.