Tag: 2022

A systematic review and meta-analysis of long term physical and mental sequelae of COVID-19 pandemic: call for research priority and action

Abstract:

The long-term physical and mental sequelae of COVID-19 are a growing public health concern, yet there is considerable uncertainty about their prevalence, persistence and predictors. We conducted a comprehensive, up-to-date meta-analysis of survivors’ health consequences and sequelae for COVID-19. PubMed, Embase and the Cochrane Library were searched through Sep 30th, 2021. Observational studies that reported the prevalence of sequelae of COVID-19 were included. Two reviewers independently undertook the data extraction and quality assessment.

Of the 36,625 records identified, a total of 151 studies were included involving 1,285,407 participants from thirty-two countries. At least one sequelae symptom occurred in 50.1% (95% CI 45.4-54.8) of COVID-19 survivors for up to 12 months after infection. The most common investigation findings included abnormalities on lung CT (56.9%, 95% CI 46.2–67.3) and abnormal pulmonary function tests (45.6%, 95% CI 36.3–55.0), followed by generalized symptoms, such as fatigue (28.7%, 95% CI 21.0–37.0), psychiatric symptoms (19.7%, 95% CI 16.1–23.6) mainly depression (18.3%, 95% CI 13.3–23.8) and PTSD (17.9%, 95% CI 11.6–25.3), and neurological symptoms (18.7%, 95% CI 16.2–21.4), such as cognitive deficits (19.7%, 95% CI 8.8–33.4) and memory impairment (17.5%, 95% CI 8.1–29.6).

Subgroup analysis showed that participants with a higher risk of long-term sequelae were older, mostly male, living in a high-income country, with more severe status at acute infection. Individuals with severe infection suffered more from PTSD, sleep disturbance, cognitive deficits, concentration impairment, and gustatory dysfunction. Survivors with mild infection had high burden of anxiety and memory impairment after recovery.

Our findings suggest that after recovery from acute COVID-19, half of survivors still have a high burden of either physical or mental sequelae up to at least 12 months. It is important to provide urgent and appropriate prevention and intervention management to preclude persistent or emerging long-term sequelae and to promote the physical and psychiatric wellbeing of COVID-19 survivors.

Source: Zeng N, Zhao YM, Yan W, Li C, Lu QD, Liu L, Ni SY, Mei H, Yuan K, Shi L, Li P, Fan TT, Yuan JL, Vitiello MV, Kosten T, Kondratiuk AL, Sun HQ, Tang XD, Liu MY, Lalvani A, Shi J, Bao YP, Lu L. A systematic review and meta-analysis of long term physical and mental sequelae of COVID-19 pandemic: call for research priority and action. Mol Psychiatry. 2022 Jun 6:1–11. doi: 10.1038/s41380-022-01614-7. Epub ahead of print. PMID: 35668159; PMCID: PMC9168643. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9168643/ (Full text)

Intracellular Nutritional Biomarker Differences in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome Subjects and Healthy Controls

Abstract:

Objectives

A comparison of the nutritional biomarkers between ME/CFS subjects and healthy controls (HC) was undertaken on secondary data collected from an IRB approved cross-sectional study in ME/CFS patients.

Methods

ME/CFS participants were recruited per the 2018 revised Canadian Clinical Case Definition for ME/CFS along with age matched HCs. Self-reported information on demographics and supplement use was collected, and body mass index calculated. HEI was calculated from Willet FFQ and multiple day 24-hour recall data, and severity of fatigue measured by Multidimensional Fatigue Inventory (MFI). Lymphocyte transformation assay by SpectraCell Lab (Houston, TX) was employed for intracellular micronutrient status. A series of two-tailed Mann-Whitney U tests (ɑ = 0.05) were performed for the non-parametric data expressed as mean ± standard error of the mean. All statistical analyses were conducted in IBM SPSS Statistics version 25 (Armonk, NY).

Results

Out of the 21 participants (11 ME/CFS and 10 HC), 82% of ME/CFS and 50% of HC were female. Higher fatigue scores were observed in ME/CFS (16.64 ± 1.36) than HC (10.78 ± 2.14). ME/CFS had better HEI scores (63.36 ± 13.44) than the HC (38.55 ± 12.29). However, despite better diet quality and supplementation, ME/CFS group showed lower intracellular Vitamin B3 and manganese (Mn) (86.3 ± 2.42 and 53.6 ± 2.81 respectively) but higher calcium (Ca) (57.5 ± 3.55) as compared to HC (97.2 ± 2.31, 64.5 ± 1.87 and 46.5 ± 0.96 respectively).

Conclusions

The results align with the current literature on indications of mitochondrial dysfunction in ME/CFS. Reduced intracellular vit B3 provides suboptimal production of the NAD(P)(H)-cofactor family, thus affecting mitochondrial function and consequently energy production. The aberration in energy metabolism is compounded by other factors, such as reduced Mn but higher Ca intracellular levels seen in this study indicating disruptions in oxidative stress pathways, resulting in debilitating fatigue experienced by individuals with ME/CFS.

Source: Priya Krishnakumar, Camila Jaramillo, Shawn Kurian, Wendy Levy, Cara Milman, Nadine Mikati, Fatma Huffman, Maria Abreu, Amanpreet Cheema, Intracellular Nutritional Biomarker Differences in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome Subjects and Healthy Controls, Current Developments in Nutrition, Volume 6, Issue Supplement_1, June 2022, Page 745, https://doi.org/10.1093/cdn/nzac062.014

Is post-COVID syndrome an autoimmune disease?

Abstract:

Introduction: Post-COVID syndrome (PCS) is recognized as a new entity in the context of SARS-CoV-2 infection. Though its pathogenesis is not completely understood, persistent inflammation from acute illness and the development of autoimmunity play a critical role in its development.

Areas covered: The mechanisms involved in the emergence of PCS, their similarities with post-viral and post-care syndromes, its inclusion in the spectrum of autoimmunity and possible targets for its treatment.

Expert opinion: An autoimmune phenomenon plays a major role in most causative theories explaining PCS. There is a need for both PCS definition and classification criteria (including severity scores). Longitudinal and controlled studies are necessary to better understand this new entity, and to find what additional factors participate into its development. With the high prevalence of COVID-19 cases worldwide, together with the current evidence on latent autoimmunity in PCS, we may observe an increase of autoimmune diseases (ADs) in the coming years. Vaccination’s effect on the development of PCS and ADs will also receive attention in the future. Health and social care services need to develop a new framework to deal with PCS.

Source: Anaya JM, Herrán M, Beltrán S, Rojas M. Is post-COVID syndrome an autoimmune disease? Expert Rev Clin Immunol. 2022 Jun 14:1-14. doi: 10.1080/1744666X.2022.2085561. Epub ahead of print. PMID: 35658801. https://pubmed.ncbi.nlm.nih.gov/35658801/

Comprehensive clinical assessment identifies specific neurocognitive deficits in working-age patients with long-COVID

Abstract:

Introduction: There have been more than 425 million COVID-19 infections worldwide. Post-COVID illness has become a common, disabling complication of this infection. Therefore, it presents a significant challenge to global public health and economic activity.

Methods: Comprehensive clinical assessment (symptoms, WHO performance status, cognitive testing, CPET, lung function, high-resolution CT chest, CT pulmonary angiogram and cardiac MRI) of previously well, working-age adults in full-time employment was conducted to identify physical and neurocognitive deficits in those with severe or prolonged COVID-19 illness.

Results: 205 consecutive patients, age 39 (IQR30.0-46.7) years, 84% male, were assessed 24 (IQR17.1-34.0) weeks after acute illness. 69% reported ≥3 ongoing symptoms. Shortness of breath (61%), fatigue (54%) and cognitive problems (47%) were the most frequent symptoms, 17% met criteria for anxiety and 24% depression. 67% remained below pre-COVID performance status at 24 weeks. One third of lung function tests were abnormal, (reduced lung volume and transfer factor, and obstructive spirometry). HRCT lung was clinically indicated in <50% of patients, with COVID-associated pathology found in 25% of these. In all but three HRCTs, changes were graded ‘mild’. There was an extremely low incidence of pulmonary thromboembolic disease or significant cardiac pathology. A specific, focal cognitive deficit was identified in those with ongoing symptoms of fatigue, poor concentration, poor memory, low mood, and anxiety. This was notably more common in patients managed in the community during their acute illness.

Conclusion: Despite low rates of residual cardiopulmonary pathology, in this cohort, with low rates of premorbid illness, there is a high burden of symptoms and failure to regain pre-COVID performance 6-months after acute illness. Cognitive assessment identified a specific deficit of the same magnitude as intoxication at the UK drink driving limit or the deterioration expected with 10 years ageing, which appears to contribute significantly to the symptomatology of long-COVID.

Source: Holdsworth DA, Chamley R, Barker-Davies R, O’Sullivan O, Ladlow P, Mitchell JL, Dewson D, Mills D, May SLJ, Cranley M, Xie C, Sellon E, Mulae J, Naylor J, Raman B, Talbot NP, Rider OJ, Bennett AN, Nicol ED. Comprehensive clinical assessment identifies specific neurocognitive deficits in working-age patients with long-COVID. PLoS One. 2022 Jun 10;17(6):e0267392. doi: 10.1371/journal.pone.0267392. PMID: 35687603; PMCID: PMC9187094. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9187094/ (Full text)

Increased risks of cancer and autoimmune disease among the first-degree relatives of patients with myalgic encephalomyelitis (ME)/chronic fatigue syndrome (CFS)

Background: Myalgic encephalomyelitis (ME)/chronic fatigue syndrome (CFS) is a disabling multi-system complex disorder with prevalence of 875 per 100,000 (up to 3.4 million people) in the United States. There are no known etiologic or risk factors and no approved treatments for ME/CFS. We conducted a molecular epidemiologic study to test the hypothesis that ME/CFS may be an autoimmune disease (AID) and explore the link between ME/CFS and cancer, specifically hematologic malignancies.Methods: Our clinic-based study involved carefully selected cases with confirmed diagnosis of ME/CFS (n=59) and healthy controls (n=54) frequency matched to cases on age, gender and ethnicity. During structured interviews, detailed multi-generation pedigrees, epidemiologic and medical questionnaires, and biospecimen were obtained on all subjects. Statistical analysis of pedigree data involved comparison of cases and controls with respect to the prevalence and cumulative incidence of AID and cancer among their first-degree relatives. For unadjusted analysis, risk ratios, 95% confidence intervals (CI), and p-values were calculated. For age-adjusted analyses, cumulative incidence estimates were compared using the log-rank test.

Results: The prevalence of AID was significantly higher among the first-degree relatives of cases compared to those of controls (OR=5.30; 95%CI: 1.83-15.38; p=0.001). The prevalence of AID among mothers was 14% for cases and 1.9% for controls (p=0.03). 11.2% of the first-degree relatives of cases had an AID compared to 3.1% of the relatives of controls (prevalence ratio=3.71; 95% CI: 1.74-7.88; p=0.0007). The cumulative incidence of AID among the first-degree relatives of ME/CFS cases was 9.4% compared to 2.7% for those of the controls (p=0.0025). First-degree relatives of ME/CFS cases had a significantly higher prevalence of any cancer compared to the relatives of unrelated controls (OR=4.06, 95%CI: 1.84-8.96, p=0.0005). Age-adjusted analysis revealed significantly higher (p=0.03) cumulative incidence of any cancer among the first-degree relatives of cases (20%) compared to the relatives of controls (15.4%). The cumulative incidence of hematologic cancers was also significantly higher among the relatives of cases (p<0.05).

Conclusions: We found statistically significant increased risks of AID and cancer among the first-degree relatives of ME/CFS cases. Our findings implicate immune dysregulation as an underlying mechanism, providing etiologic clues and leads for prevention. Given symptomatic similarities between ‘long COVID’ and ME/CFS, it is predicted that there will be a significant increase in incidence of ME/CFS as the result of COVID-19 pandemic. Our findings may enable defining a subset of COVID-19 patients who could be at risk of developing ME/CFS, and who may benefit from treatments used for certain AIDs.

Source: Roxana Moslehi, Anil Kumar, Amiran Dzutsev. Increased risks of cancer and autoimmune disease among the first-degree relatives of patients with myalgic encephalomyelitis (ME)/chronic fatigue syndrome (CFS) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 34. https://aacrjournals.org/cancerres/article/82/12_Supplement/34/700144

 

“Long COVID” results after hospitalization for SARS-CoV-2 infection

Abstract:

Long-term sequelae of symptomatic infection caused by SARS-CoV-2 are largely undiscovered. We performed a prospective cohort study on consecutively hospitalized Sars-CoV-2 patients (March-May 2020) for evaluating COVID-19 outcomes at 6 and 12 months. After hospital discharge, patients were addressed to two follow-up pathways based on respiratory support needed during hospitalization. Outcomes were assessed by telephone consultation or ambulatory visit.

Among 471 patients, 80.9% received no respiratory support during hospitalization; 19.1% received non-invasive ventilation (NIV) or invasive mechanical ventilation (IMV). 58 patients died during hospitalization, therefore 413 were enrolled for follow-up. At 6 months, among 355 patients, the 30.3% had any symptoms, 18.0% dyspnea, 6.2% neurological symptoms. Fifty-two out of 105 had major damages in interstitial computed tomography images. NIV/IMV patients had higher probability to suffer of symptoms (aOR = 4.00, 95%CI:1.99-8.05), dyspnea (aOR = 2.80, 95%CI:1.28-6.16), neurological symptoms (aOR = 9.72, 95%CI:2.78-34.00). At 12 months, among 344, the 25.3% suffered on any symptoms, 12.2% dyspnea, 10.1% neurological symptoms. Severe interstitial lesions were present in 37 out of 47 investigated patients.

NIV/IMV patients in respect to no respiratory support, had higher probability of experiencing symptoms (aOR = 3.66, 95%CI:1.73-7.74), neurological symptoms (aOR = 8.96, 95%CI:3.22-24.90). COVID-19 patients showed prolonged sequelae up to 12 months, highlighting the need of follow-up pathways for post-COVID-19 syndrome.

Source: Rigoni M, Torri E, Nollo G, Donne LD, Rizzardo S, Lenzi L, Falzone A, Cozzio S. “Long COVID” results after hospitalization for SARS-CoV-2 infection. Sci Rep. 2022 Jun 10;12(1):9581. doi: 10.1038/s41598-022-13077-5. PMID: 35688830; PMCID: PMC9185134. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9185134/ (Full text)

Immunogenetic studies in myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS)

Myalgic encephalopathy/chronic fatigue syndrome (ME/CFS) is a chronic and debilitating disease that affects about 0.1-0.2% of the general population. The core symptoms are persistent debilitating fatigue, post-exertional malaise (PEM) and cognitive dysfunction. Most symptoms of ME/CFS are not disease specific. Additionally, there is a lack of both biomarkers and diagnostic tests for the disease, which makes accurate diagnosis difficult.

More than 20 different patient classifications and diagnostic criteria have emerged over the last four decades. Due to this, the patient population can be quite heterogeneous in terms of clinical symptoms and the extent to which the disease impacts quality of life.

There are several different theories that aim to explain the disease development of ME/CFS. In this thesis, we have taken as our starting point the growing evidence for an immunological background for ME/CFS pathogenesis. Several studies have pointed to altered NK cells, autoantibodies and T cell abnormalities in ME/CFS patients.

In addition, several genetic studies reported significant associations in various immunologically relevant genes. Most of these previous studies have been suboptimal and included heterogeneous patient populations and/or few patients in total.

Therefore, we aimed to gain a better understanding of the role of immunologically relevant genes and disease development of ME/CFS.

To do this, we employed known strategies from genetic studies in autoimmune disease and applied them to ME/CFS. We used strict quality control and included, to the best of our knowledge, the largest cohort diagnosed with the Canadian consensus criteria.

In paper I, the main goal was to follow up previously performed work by our group that reported associations between ME/CFS and HLA-C: 07: 04 and HLA-DQB1: 03: 03 alleles. The HLA (human leukocyte antigen) region consists a multitude of immunologically relevant genes in addition to the HLA genes, and there is extensive and complex linkage disequilibrium (LD) in the region.

The previously observed association signals in the HLA region were fine-mapped by genotyping five additional classical HLA loci and 5,342 SNPs (single nucleotide variants) in 427 Norwegian ME/CFS patients, diagnosed according to the Canadian consensus criteria, and 480 healthy Norwegian controls. The analysis revealed two independent association signals (p ≤ 0.001) represented by the genetic variants rs4711249 in the HLA class I region and rs9275582 in the HLA class II region.

The primary association signal in the HLA class II region was located in the vicinity of the HLA-DQ genetic region, most likely due to the HLA-DQB1 gene. In particular, amino acid position 57 (aspartic acid / alanine) in the peptide binding pit of HLA-DQB1, or an SNP upstream of HLA-DQB1 seemed to explain the association signal we observed in the HLA class II region.

In the HLA class I region, the putative primary locus was not as clear and could possibly lie outside the classical HLA genes (the association signal spans several genes DDR1, GTF2H4, VARS2, SFTA2 and DPCR1) with expression levels influenced by the ME/CFS associated SNP genotypes.

Interestingly, we also observed that > 60% of the patients who responded to cyclophosphamide treatment for ME/CFS had either the rs4711249 risk allele and/or DQB1* 03:03 versus 12% of the patients who did not respond to the treatment. Our findings suggest the involvement of the HLA region, and in particular the HLA-DQB1 gene, in ME/CFS.

Although our study is the largest to date, it is still a relatively small study in the context of genetic studies. Our findings need to be replicated in much larger, statistically more representative, cohorts.

In particular, it is necessary to investigate the involvement of HLA- 12 DQB1, a gene that contains alleles that increase the risk of several established autoimmune diseases such as celiac disease.

In paper II, we aimed to investigate immunologically relevant genes using a genotyping array (iChip) targeting immunological gene regions previously associated with different autoimmune diseases.

In addition to the Norwegian cohort of 427 ME/CFS patients (the Canadian consensus criteria), we also analyzed data from two replication cohorts, a Danish one of 460 ME/CFS patients (Canadian consensus criteria) and a data set from the UK Biobank of 2105 self-reported CFS patients.

To the best of our knowledge, this is the first ME/CFS genetic association study of this magnitude and it included more than 2,900 patients in total (of whom 887 are diagnosed according to Canadian consensus criteria).

We found no ME/CFS risk variants with a genome wide significance level (p<5×10-8), but we identified six gene regions (TPPP, LINC00333, RIN3. IGFBP/IGFBP3, IZUMO1/MAMSTR and ZBTB46/STMN3) with possible association with ME/CFS which require further follow-up in future studies in order to assess whether they are real findings or not.

Interestingly, these genes are expressed in disease-relevant tissue, e.g. brain, nerve, skeletal muscle and blood, including immune cells (subgroups of T cells, B cells, NK cells and monocytes).

Furthermore, several of the ME/CFS associated SNP genotypes are associated with differential expression levels of these genes. Although we could not identify statistically convincing associations with genetic variants across the three cohorts, we believe that our data sets and analysis represent an important step in the ME/CFS research field.

Our study demonstrated that for the future understanding of the genetic architecture of ME/CFS much larger studies are required to established reliable associations.

In paper III, we wanted to investigate previous findings from a genome wide association study of 42 ME/CFS patients who reported significant association with two SNPs in the T cell receptor alpha (TRA) locus (P-value<5×10-8).

In order to replicate these previously reported findings, we used a large Norwegian ME/CFS cohort (409 cases and 810 controls) and data from the UK Biobank (2105 cases and 4786 controls). We examined a number of SNPs in the TRA locus, including the two previous ME/CFS-associated variants, rs11157573 and rs17255510. No statistically significant associations were observed in either the Norwegian cohort or UK biobank cohorts.

Nevertheless, other SNPs in the region showed weak signs of association (P-value <0.05) in the UK Biobank cohort and meta-analyzes of Norwegian and UK Biobank cohorts, but did not remain associated after applying correction for multiple testing. Thus, we could not confirm associations with genetic variants in the TRA locus in this study.

Source: Riad Hajdarevic. PhD thesis (University of Oslo) Electronic copies must be ordered. https://www.med.uio.no/klinmed/english/research/news-and-events/events/disputations/2022/hajdarevic-riad.html

Survey of Anti-Pathogen Antibody Levels in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome

Abstract:

Infectious pathogens are implicated in the etiology of myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) because of the occurrence of outbreaks of the disease. While a number of different infectious agents have been associated with the onset of ME/CFS, the identity of a specific organism has been difficult to determine in individual cases. The aim of our study is to survey ME/CFS subjects for evidence of an infectious trigger and/or evidence of immune dysregulation via serological testing of plasma samples for antibodies to 122 different pathogen antigens.
Immune profiles were compared to age-, sex-, and BMI-matched controls to provide a basis for comparison. Antibody levels to individual antigens surveyed in this study do not implicate any one of the pathogens in ME/CFS, nor do they rule out common pathogens that frequently infect the US population. However, our results revealed sex-based differences in steady-state humoral immunity, both within the ME/CFS cohort and when compared to trends seen in the healthy control cohort.
Source: O’Neal AJ, Glass KA, Emig CJ, Vitug AA, Henry SJ, Shungu DC, Mao X, Levine SM, Hanson MR. Survey of Anti-Pathogen Antibody Levels in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome. Proteomes. 2022; 10(2):21. https://doi.org/10.3390/proteomes10020021 https://www.mdpi.com/2227-7382/10/2/21/htm (Full text)

SARS-CoV-2 infection and persistence throughout the human body and brain

Abstract:

COVID-19 is known to cause multi-organ dysfunction1-3 in acute infection, with prolonged symptoms experienced by some patients, termed Post-Acute Sequelae of SARS-CoV-2 (PASC)4-5. However, the burden of infection outside the respiratory tract and time to viral clearance is not well characterized, particularly in the brain3,6-14.
We performed complete autopsies on 44 patients with COVID-19 to map and quantify SARS-CoV-2 distribution, replication, and cell-type specificity across the human body, including brain, from acute infection through over seven months following symptom onset. We show that SARS-CoV-2 is widely distributed, even among patients who died with asymptomatic to mild COVID-19, and that virus replication is present in multiple extrapulmonary tissues early in infection.
Further, we detected SARS-CoV-2 RNA in multiple anatomic sites, including regions throughout the brain, for up to 230 days following symptom onset. Despite extensive distribution of SARS-CoV-2 in the body, we observed a paucity of inflammation or direct viral cytopathology outside of the lungs. Our data prove that SARS-CoV-2 causes systemic infection and can persist in the body for months.
Source: Daniel Chertow, Sydney Stein, Sabrina Ramelli et al. SARS-CoV-2 infection and persistence throughout the human body and brain, 20 December 2021, PREPRINT (Version 1) available at Research Square [https://doi.org/10.21203/rs.3.rs-1139035/v1] https://www.researchsquare.com/article/rs-1139035/v1 https://www.nature.com/articles/s41586-022-05542-y (Full text)

Post-acute COVID-19 cognitive impairment and decline uniquely associate with kynurenine pathway activation: a longitudinal observational study

Abstract:

Cognitive impairment and function post-acute mild to moderate COVID-19 are poorly understood. We report findings of 128 prospectively studied SARS-CoV-2 positive patients. Cognition and olfaction were assessed at 2-, 4- and 12-months post-diagnosis. Lung function, physical and mental health were assessed at 2-month post diagnosis. Blood cytokines, neuro-biomarkers, and kynurenine pathway (KP) metabolites were measured at 2-, 4-, 8- and 12-months. Mild to moderate cognitive impairment (demographically corrected) was present in 16%, 23%, and 26%, at 2-, 4- and 12-months post diagnosis, respectively. Overall cognitive performance mildly, but significantly (p<.001) declined. Cognitive impairment was more common in those with anosmia (p=.05), but only at 2 months. KP metabolites quinolinic acid, 3-hydroxyanthranilic acid, and kynurenine were significantly (p<.001) associated with cognitive decline. The KP as a unique biomarker offers a potential therapeutic target for COVID-19-related cognitive impairment.

Source: Lucette A. Cysique, David Jakabek, Sophia G. Bracken, Yasmin Allen-Davidian, Benjamin Heng, Sharron Chow, Mona Dehhaghi, Ananda Staats Pires, David R. Darley, Anthony Byrne, Chansavath Phetsouphanh, Anthony Kelleher, Gregory J. Dore, Gail V. Matthews, Gilles J Guillemin, Bruce J. Brew. Post-acute COVID-19 cognitive impairment and decline uniquely associate with kynurenine pathway activation: a longitudinal observational study. medRxiv 2022.06.07.22276020; doi: https://doi.org/10.1101/2022.06.07.22276020 https://www.medrxiv.org/content/10.1101/2022.06.07.22276020v1.full-text (Full text)