Toevallig is er gister in Nature een review paper over long-Covid gepubliceerd.
https://www.nature.com/articles/s41577-023-00904-7quote:
Long COVID is the patient-coined term for the disease entity whereby persistent symptoms ensue in a significant proportion of those who have had COVID-19, whether asymptomatic, mild or severe. Estimated numbers vary but the assumption is that, of all those who had COVID-19 globally, at least 10% have long COVID. The disease burden spans from mild symptoms to profound disability, the scale making this a huge, new health-care challenge. Long COVID will likely be stratified into several more or less discrete entities with potentially distinct pathogenic pathways. The evolving symptom list is extensive, multi-organ, multisystem and relapsing–remitting, including fatigue, breathlessness, neurocognitive effects and dysautonomia. A range of radiological abnormalities in the olfactory bulb, brain, heart, lung and other sites have been observed in individuals with long COVID. Some body sites indicate the presence of microclots; these and other blood markers of hypercoagulation implicate a likely role of endothelial activation and clotting abnormalities. Diverse auto-antibody (AAB) specificities have been found, as yet without a clear consensus or correlation with symptom clusters. There is support for a role of persistent SARS-CoV-2 reservoirs and/or an effect of Epstein–Barr virus reactivation, and evidence from immune subset changes for broad immune perturbation. Thus, the current picture is one of convergence towards a map of an immunopathogenic aetiology of long COVID, though as yet with insufficient data for a mechanistic synthesis or to fully inform therapeutic pathways.
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Box 2
How common is long COVID after acute infection?
Many individuals affected by long COVID never seek medical advice for their condition, presumably assuming that nothing can be done for them. Indeed, among the lowest published estimates for long COVID prevalence is the inference from a Danish population survey based on prescription records initiating new drugs or new GP visits or hospital referrals during the 6 months after acute infection140. Another recent report that based imputation of time to recovery from long COVID on patient attrition in terms of electronic health records141 has been debated on the grounds that concerns about methodology and interpretation mean that the study offers an overly optimistic view of long COVID recovery142. Counting long COVID cases remains complex due to the use of different methodologies and definitions, especially defining long COVID as symptoms persisting for at least 4 weeks versus 12 weeks from the start of acute infection. Counting method differences largely account for the array of long COVID frequencies cited, from below 10% to around 60% across studies. The ‘COVID in Scotland’ study including ~33,000 individuals with laboratory-confirmed COVID-19 found that, by 18 months, 6% had not recovered at all and 42% had partially recovered143. From a recent meta-analysis covering approximately 0.75 million cases of COVID-19 across many countries, an overall figure of 45% experienced persistent symptoms at 4 months, irrespective of hospitalization status144. The REACT-2 survey (Imperial College, UK) is illuminating, being a longitudinal community study of over 606,000 people in England surveyed about their symptoms145. Long COVID prevalence varied with time after acute infection and the number of symptoms. People gradually recovered with time from onset but, at 4 weeks after first symptoms, around 40% still reported one or more symptoms. By 12 weeks, this had dropped minimally to 38%. Prevalence was essentially sustained at this level through the next 6 months of the survey period. The results from this random survey in the community show that most of the observed recovery for the lucky 60% occurs during the first 4 weeks, but those still showing symptoms at 12 weeks find themselves on the poorly charted plateau to becoming ‘long-haulers.’ Another study analysed data from 10 longitudinal study samples of patients with COVID-19 and 1.1 million individuals from electronic health-care records, finding that 7.8% to 17% of participants had long COVID symptoms at 12 weeks146. In the UK Office for National Statistics data, 24% of the current national caseload of 2.1 million individuals who had SARS-CoV-2 infection reported persistent symptoms for over 2 years. That is, over half a million people in the UK alone have had long COVID for more than 2 years.
Although there are anecdotal reports of individuals with gradual improvement and remission beyond 2 years, few studies have yet explored full recovery or the factors that favour this. The UK Office for National Statistics data is informative to the extent that, although new long COVID cases continued to stack up in large numbers during the Omicron wave of 2022, the cumulative total reporting long COVID plateaued or fell only slightly, to around 2–2.3 million, equivalent to around 3% of the population. There is remarkable convergence in long COVID prevalence and symptom profiles reported globally and cross-culturally147.
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Box 4 Evidence for end-organ damage from imaging studies
Lung
A central conundrum in the decoding of long COVID has been the disconnect between breathlessness as one of the defining symptoms and a tendency for those with long COVID to show profound desaturation with even mild exertion in the face of often unremarkable lung CT and MRI findings. Insights have been gained through the use of 129Xe MRI and CT pulmonary vascular measurements to investigate the relationship of persistent symptoms and exercise limitation in long COVID39. 129Xe MRI measurements were lower in the long COVID group than in controls, associated with CT pulmonary vascular density, lung carbon monoxide diffusing capacity, exercise capacity and dyspnoea. These studies are evidence of a failure of gas transfer in the vascular compartment as a pathogenic mechanism in long COVID. There is also increasing acceptance of more routine imaging modalities for the investigation of respiratory symptoms of long COVID. Dual-energy CT demonstrates perfusion defects in the lungs of approximately 60% of those with respiratory symptoms of long COVID at 3 months after infection and demonstrates persistent macrothrombosis (visible clots evidenced by filling defects in the pulmonary arteries) in 5% of patients30.
Heart
If lung imaging studies remain some way from offering a pathological correlate for exercise intolerance and breathlessness, one might make a similar case for the less-than-clear relationship between symptoms and cardiac imaging. Chest pain is a hallmark long COVID symptom in most of the symptom cluster studies. From large health-care data sets, there is an enhanced risk of cardiovascular disease in the 12-month period after COVID-19 infection130. Even individuals with SARS-CoV-2 infection who were not hospitalized show an increased 1-year risk of stroke, transient ischaemic attack, myocarditis, angina, pulmonary embolism and heart failure. However, identifying the radiological correlates of this enhanced risk has been controversial, with divergent findings29,32,156. Cardiac imaging studies across individuals with asymptomatic, mild and severe COVID-19 report abnormal MRI findings spanning a wide range, from 0% to 78%. The nature of this divergence remains unclear, but may relate to differences in the use of baseline, pre-COVID-19 data29,32. Late gadolinium enhancement indicative of myocarditis was similarly observed in 0–45% of those imaged156. Further studies are warranted to relate specific long COVID cardiac symptoms, such as chest pain, to radiological findings.
Brain
In terms of MRI brain imaging, the UK Biobank cohort study has the methodological advantage of matched images for each participant, spanning a 3-year interval before and after infection35. The findings were not specifically linked to the reporting of long COVID symptoms in this population. Significant changes following infection were reported for brain and cerebrospinal fluid volume, lateral ventricle volume, and the temporal cortex functional network. Notably, there was also cognitive decline, which correlated with changes in the volume of cognitive lobule crus II of the cerebellum35. Such longitudinal studies highlight a confounder intrinsic to our long COVID data sets, in that we generally lack individual comparator data sets prior to infection. Long-term changes to smell and taste in long COVID have been considered by a large number of imaging studies36. Again, findings are rather variable, but a number show significant reduction in olfactory bulb volume, which is in line with changes shown following acute disease by histopathology and transcriptomics, potentially indicating ongoing T cell immunopathology in the absence of detectable virus157.
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The oncoming burden of long COVID faced by patients, health-care providers, governments and economies is so large as to be unfathomable, which is possibly why minimal high-level planning is currently allocated to it. If 10% of acute infections lead to persistent symptoms, it could be predicted that ~400 million individuals globally are in need of support for long COVID.
Random guy on the internet: "Het is gewoon psychisch joh, dat long-covid"