Health Care Personnel Workdays Lost and Direct Health Care Salary Costs Incurred due to COVID-19 Infection in the Age of Widespread Vaccine Availability.

BACKGROUND: Vaccination against coronavirus disease 2019 (COVID-19) can mitigate the burden of health care worker (HCW) infection. We investigate the burden of HCW illness and its associated direct health care personnel costs in the setting of widespread vaccine availability and explore factors influencing these outcomes. METHODS: This multicenter prospective study followed HCWs over an 8-month period from January to August 2023. Data recorded included incident COVID-19 infection, symptom burden, workdays missed, and vaccine history. Workdays lost due to illness were used to calculate direct health care personnel costs due to COVID-19 infection. Univariate analysis and multivariable regression investigated the factors associated with workdays lost and direct health care personnel. RESULTS: In total, 1218 participants were enrolled and followed for 8 months, with 266 incidents of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, 1191 workdays lost, and health care personnel costs of €397 974. Multivariable regression revealed that workdays lost were associated with incomplete primary COVID-19 vaccination course. Being unvaccinated, older age, and male were associated with increased health care personnel costs. CONCLUSIONS: Health care workdays lost remain a significant issue and are associated with health care system burden despite vaccine availability. These can be mitigated via targeted implementation of vaccine programs. Seasonal variation in health care workdays lost should inform workforce planning to accommodate surge periods.

Immune response in vaccinated healthcare workers with frequent COVID-19 infections is characterised by blunted IFNγ and IL-2 responses to SARS-CoV-2 variants.

Healthcare workers (HCWs) are at increased risk of SARS-CoV-2 infection. Despite widespread vaccination, some HCWs develop frequent symptomatic infection. We hypothesised that HCWs with frequent symptomatic COVID-19 have impaired T and B cell mediated immunity to SARS-CoV-2. Vaccinated HCWs with no prior COVID infection (n = 9), asymptomatic recent infection (n = 10), and frequent recent infection (n = 15) were recruited from a longitudinal HCW cohort study. Whole blood stimulation with SARS-CoV-2 variants (Wuhan, B.1.617, BA.2, BA.2.75, BA.4/5, XBB.1.5, BQ.1.1) was performed, with IFNγ and IL-2 responses, total IgG produced, and anti-Spike antibody neutralising capacity measured. Frequent infections had similar IFNγ and IL-2 responses to the never infected group, with significantly higher responses in the asymptomatic group. The frequent cohort had higher IgG responses to Delta and BA.4/5 and higher neutralising capacity against Omicron variants. An immune signature of blunted IL-2 and IFNγ in frequent infections may identify HCWs at increased risk of further infection.

Effect of Immunosuppression on the Immune Response to SARS-CoV-2 Infection and Vaccination.

Immunosuppressive treatment in patients with rheumatic diseases can maintain disease remission but also increase risk of infection. Their response to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccination is frequently blunted. In this study we evaluated the effect of immunosuppression exposure on humoral and T cell immune responses to SARS-CoV-2 infection and vaccination in two distinct cohorts of patients; one during acute SARS-CoV-2 infection and 3 months later during convalescence, and another prior to SARS-CoV-2 vaccination, with follow up sampling 6 weeks after vaccination. Results were compared between rituximab-exposed (in previous 6 months), immunosuppression-exposed (in previous 3 months), and non-immunosuppressed groups. The immune cell phenotype was defined by flow cytometry and ELISA. Antigen specific T cell responses were estimated using a whole blood stimulation interferon-γ release assay. A focused post-vaccine assessment of rituximab-treated patients using high dimensional spectral cytometry was conducted. Acute SARS-CoV-2 infection was characterised by T cell lymphopenia, and a reduction in NK cells and naïve CD4 and CD8 cells, without any significant differences between immunosuppressed and non-immunosuppressed patient groups. Conversely, activated CD4 and CD8 cell counts increased in non-immunosuppressed patients with acute SARS-CoV-2 infection but this response was blunted in the presence of immunosuppression. In rituximab-treated patients, antigen-specific T cell responses were preserved in SARS-CoV-2 vaccination, but patients were unable to mount an appropriate humoral response.

Research priorities in HIV, aging and rehabilitation: building on a framework with the Canada-International HIV and Rehabilitation Research Collaborative.

BACKGROUND: In 2016, the Canada-International HIV and Rehabilitation Research Collaborative established a framework of research priorities in HIV, aging and rehabilitation. Our aim was to review and identify any new emerging priorities from the perspectives of people living with HIV, clinicians, researchers, and representatives from community organizations. METHODS: We conducted a multi-stakeholder international consultation with people living with HIV, researchers, clinicians and representatives of community-based organizations. Stakeholders convened for a one-day Forum in Manchester, United Kingdom (UK) to discuss research priorities via a web-based questionnaire and facilitated discussions. We analyzed data using conventional content analytical techniques and mapped emerging priorities onto the foundational framework. RESULTS: Thirty-five stakeholders from the UK(n = 29), Canada(n = 5) and Ireland(n = 1) attended the Forum, representing persons living with HIV or representatives from community-based organizations(n = 12;34%), researchers or academics(n = 10;28%), service providers(n = 6;17%), clinicians(n = 4;11%); and trainees(n = 4;11%). Five priorities mapped onto the Framework of Research Priorities across three content areas: A-Episodic Health and Disability Aging with HIV (disability, frailty, social participation), B-Rehabilitation Interventions for Healthy Aging across the Lifespan (role, implementation and impact of digital and web-based rehabilitation interventions) and C-Outcome Measurement in HIV and Aging (digital and web-based rehabilitation health technology to measure physical activity). Stakeholders indicated methodological considerations for implementing digital and web-based rehabilitation interventions into research and practice and the importance of knowledge transfer and exchange among the broader community. CONCLUSION: Results highlight the sustained importance of the Framework of Research Priorities and provide further depth and areas of inquiry related to digital and web-based rehabilitation interventions and technology aging with HIV.

1-year quality of life and health-outcomes in patients hospitalised with COVID-19: a longitudinal cohort study.

BACKGROUND: Published studies suggest physical recovery from the COVID-19 is complex, with many individuals experiencing persistent symptoms. There is a paucity of data investigating the longer-term trajectory of physical recovery from COVID-19. METHODS: A prospective longitudinal design was utilised to investigate the impact COVID-19 has on physical functioning at 10-weeks (T1), 6-months (T2) and 1-year (T3) post-hospital discharge. Objective measures of recovery included 6-Minute Walk Test Distance (6MWTD), frailty (Clinical Frailty Scale), quantification of falls following hospital-discharge, return to work status and exercise levels. Subjective markers included symptoms (COVID-19-Specific Patient Concerns Assessment), fatigue (Chalder Fatigue Score) and health-related quality of life (HrQOL) [Short-Form-36 Health Survey Questionnaire (SF-36-II)]. Univariate analysis was performed using t-test, Wilcoxon rank-sum, and Chi-squared test, paired analysis using one-way analysis of variance and Krustal Wallis testing and correlation analysis with Spearman correlation tests. RESULTS: Sixty-one subjects participated. Assessments were conducted at a median of 55 days(T1), 242 days(T2), and 430 days(T3) following hospital-discharge. 6MWTD improved significantly overtime (F = 10.3, p < 0.001) from 365(209)m at T1 to 447(85)m at T3, however remained below population norms and with no associated improvement in perceived exertion. Approximately half (n = 27(51%)) had returned to pre-diagnosis exercise levels at T3. At least one concern/symptom was reported by 74%, 59% and 64% participants at T1, T2 and T3 respectively. Fatigue was the most frequently reported symptom at T1(40%) and T2(49%), while issues with memory/concentration was the most frequently reported at T3(49%). SF-36 scores did not change in any domain over the study period, and scores remained lower than population norms in the domains of physical functioning, energy/vitality, role limitations due to physical problems and general health. Return-to-work rates are low, with 55% of participants returning to work in some capacity, and 31% of participants don't feel back to full-health at 1-year following infection. CONCLUSION: Hospitalised COVID-19 survivors report persistent symptoms, particularly fatigue and breathlessness, low HrQOL scores, sub-optimal exercise levels and continued work absenteeism 1-year following infection, despite some objective recovery of physical functioning. Further research is warranted to explore rehabilitation goals and strategies to optimise patient outcomes during recovery from COVID-19. CLINICAL MESSAGE: Hospitalised COVID-19 survivors report significant ongoing rehabilitation concerns 1-year following infection, despite objective recovery of physical functioning. Our findings suggest those who returned to exercise within 1-year may have less fatigue and breathlessness. The impact of exercise, and other rehabilitative strategies on physical functioning outcomes following COVID-19 should be investigated in future research.

Kinetics of the Severe Acute Respiratory Syndrome Coronavirus 2 Antibody Response and Serological Estimation of Time Since Infection.

BACKGROUND: Infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) induces a complex antibody response that varies by orders of magnitude between individuals and over time. METHODS: We developed a multiplex serological test for measuring antibodies to 5 SARS-CoV-2 antigens and the spike proteins of seasonal coronaviruses. We measured antibody responses in cohorts of hospitalized patients and healthcare workers followed for up to 11 months after symptoms. A mathematical model of antibody kinetics was used to quantify the duration of antibody responses. Antibody response data were used to train algorithms for estimating time since infection. RESULTS: One year after symptoms, we estimate that 36% (95% range, 11%-94%) of anti-Spike immunoglobulin G (IgG) remains, 31% (95% range, 9%-89%) anti-RBD IgG remains, and 7% (1%-31%) of anti-nucleocapsid IgG remains. The multiplex assay classified previous infections into time intervals of 0-3 months, 3-6 months, and 6-12 months. This method was validated using data from a seroprevalence survey in France, demonstrating that historical SARS-CoV-2 transmission can be reconstructed using samples from a single survey. CONCLUSIONS: In addition to diagnosing previous SARS-CoV-2 infection, multiplex serological assays can estimate the time since infection, which can be used to reconstruct past epidemics.

Von Willebrand factor propeptide in severe coronavirus disease 2019 (COVID-19): evidence of acute and sustained endothelial cell activation.

Endothelial cell (EC) activation plays a key role in the pathogenesis of pulmonary microvascular occlusion, which is a hallmark of severe coronavirus disease 2019 (COVID-19). Consistent with EC activation, increased plasma von Willebrand factor antigen (VWF:Ag) levels have been reported in COVID-19. Importantly however, studies in other microangiopathies have shown that plasma VWF propeptide (VWFpp) is a more sensitive and specific measure of acute EC activation. In the present study, we further investigated the nature of EC activation in severe COVID-19. Markedly increased plasma VWF:Ag [median (interquatile range, IQR) 608·8 (531-830)iu/dl] and pro-coagulant factor VIII (FVIII) levels [median (IQR) 261·9 (170-315) iu/dl] were seen in patients with severe severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection. Sequential testing showed that these elevated VWF-FVIII complex levels remained high for up to 3 weeks. Similarly, plasma VWFpp levels were also markedly elevated [median (IQR) 324·6 (267-524) iu/dl]. Interestingly however, the VWFpp/VWF:Ag ratio was reduced, demonstrating that decreased VWF clearance contributes to the elevated plasma VWF:Ag levels in severe COVID-19. Importantly, plasma VWFpp levels also correlated with clinical severity indices including the Sequential Organ Failure Assessment (SOFA) score, Sepsis-Induced Coagulopathy (SIC) score and the ratio of arterial oxygen partial pressure to fractional inspired oxygen (P/F ratio). Collectively, these findings support the hypothesis that sustained fulminant EC activation is occurring in severe COVID-19, and further suggest that VWFpp may have a role as a biomarker in this setting.

Clinical outcomes and adverse events in patients hospitalised with COVID-19, treated with off-label hydroxychloroquine and azithromycin.

AIMS: To assess clinical outcomes and adverse drug events in patients hospitalised with COVID-19 treated with off-label hydroxychloroquine (HCQ) and azithromycin (Az). METHODS: We performed a retrospective analysis of hospitalised patients who had a positive polymerase chain reaction test for SARS-CoV-2 and received HCQ plus Az or no targeted therapy. The primary end point was clinical improvement on day 7 defined as either hospital discharge or an improvement of 2 points on a 6-category ordinal scale. Secondary outcomes included mortality at day 28, intensive care admission, requirement for mechanical ventilation and incidence of adverse events. RESULTS: Data from a total of 134 patients were evaluated; 82 patients received HCQ/Az and 52 patients received no targeted therapy. Clinical improvement was seen in 26.8% of patients who received HCQ/Az but this was not significant. The rates of intensive care transfer and mechanical ventilation were higher in the treatment group, but these differences were not significant. Mortality at day 28 was significantly higher in the treatment group (P = .03). Hypoglycaemia elevated liver function tests and QT prolongation were monitored in both groups. The risk of QT prolongation was significantly higher in the treatment group. Treatment was stopped early in 6 (7.3%) patients due to adverse events. CONCLUSION: Although patients who received HCQ/Az were more severely ill the administration of these repurposed drugs did not result in clinical improvement and was associated with a significant increase in toxicity. This descriptive study highlights the importance of monitoring all repurposed agents for adverse events.

COVID19 coagulopathy in Caucasian patients.

Although the pathophysiology underlying severe COVID19 remains poorly understood, accumulating data suggest that a lung-centric coagulopathy may play an important role. Elevated D-dimer levels which correlated inversely with overall survival were recently reported in Chinese cohort studies. Critically however, ethnicity has major effects on thrombotic risk, with a 3-4-fold lower risk in Chinese compared to Caucasians and a significantly higher risk in African-Americans. In this study, we investigated COVID19 coagulopathy in Caucasian patients. Our findings confirm that severe COVID19 infection is associated with a significant coagulopathy that correlates with disease severity. Importantly however, Caucasian COVID19 patients on low molecular weight heparin thromboprophylaxis rarely develop overt disseminated intravascular coagulation (DIC). In rare COVID19 cases where DIC does develop, it tends to be restricted to late-stage disease. Collectively, these data suggest that the diffuse bilateral pulmonary inflammation observed in COVID19 is associated with a novel pulmonary-specific vasculopathy termed pulmonary intravascular coagulopathy (PIC) as distinct to DIC. Given that thrombotic risk is significantly impacted by race, coupled with the accumulating evidence that coagulopathy is important in COVID19 pathogenesis, our findings raise the intriguing possibility that pulmonary vasculopathy may contribute to the unexplained differences that are beginning to emerge highlighting racial susceptibility to COVID19 mortality.

Investigating incidence of and factors associated with SARS-CoV-2 infection over a nine-month period in a highly-vaccinated healthcare worker cohort.

BACKGROUND: Healthcare workers (HCWs) are at increased risk of SARS-CoV-2 infection. This risk persists despite the implementation of mitigating factors, including vaccination. The ongoing impact of incident SARS-CoV-2 infection and symptomatic COVID-19 disease in vaccinated HCWs is poorly understood. AIM: We aimed to describe the epidemiology of incident SARS-CoV-2 infections, as well as investigating the serological, clinical and demographic factors associated with developing infection. DESIGN: This was a multi-centre prospective longitudinal study followed a HCW cohort over a nine-month period. METHODS: Spike and nucleocapsid SARS-CoV-2 antibodies were measured at enrolment. Vaccination status, demographics and medical history were collated. Incident infection over the study period was recorded. Multivariable regression models investigated factors associated with nucleocapsid antibody status, incident infection and symptomatic infection. RESULTS: About 1260 participants took part, of whom n = 1006 were anti-nucleocapsid antibody positive. Negative anti-nucleocapsid antibody was associated with older age and having a known SARS-CoV-2 acquisition risk. There were n = 274 (22%) incident infections, with n = 225 (87%) diagnosed using antigen tests. Incident infections were associated with lower anti-nucleocapsid titres, increased time since previous SARS-CoV-2 infection, and having a known acquisition risk, but were not associated with vaccination status. CONCLUSIONS: This study demonstrates a high rate of incident SARS-CoV-2 infection amongst HCWs, despite broad vaccine coverage. There is a shift in diagnostics, from PCR to antigen testing. We identify at-risk groups for incident infection, and these should continue be targeted as part of risk reduction campaigns. Vaccination status and prior infection status alone are not surrogates for protection.

Long COVID: Clinical characteristics, proposed pathogenesis and potential therapeutic targets.

The emergence of persistent ill-health in the aftermath of SARS-CoV-2 infection has presented significant challenges to patients, healthcare workers and researchers. Termed long COVID, or post-acute sequelae of COVID-19 (PASC), the symptoms of this condition are highly variable and span multiple body systems. The underlying pathophysiology remains poorly understood, with no therapeutic agents proven to be effective. This narrative review describes predominant clinical features and phenotypes of long COVID alongside the data supporting potential pathogenesis of these phenotypes including ongoing immune dysregulation, viral persistence, endotheliopathy, gastrointestinal microbiome disturbance, autoimmunity, and dysautonomia. Finally, we describe current potential therapies under investigation, as well as future potential therapeutic options based on the proposed pathogenesis research.

Healthcare Worker Characteristics Associated with SARS-CoV-2 Vaccine Uptake in Ireland; a Multicentre Cross-Sectional Study.

The prevention of SARS-CoV-2 acquisition and transmission among healthcare workers is an ongoing challenge. Vaccination has been introduced to mitigate these risks. Vaccine uptake varies among healthcare workers in the absence of vaccine mandates. We investigated engagement with SARS-CoV-2 vaccination among healthcare workers and identified characteristics associated with lower vaccine uptake. This multi-site cross-sectional study recruited n = 1260 healthcare workers in both clinical and non-clinical roles over a three-month period from November 2022. Participants reported their engagement with the primary SARS-CoV-2 vaccination programme and subsequent booster programmes, as well as providing demographic, occupational and personal medical history information. Multivariable linear regression identified characteristics associated with vaccine uptake. Engagement with vaccination programmes was high, with 88% of participants receiving at least one booster dose after primary vaccination course. Younger age and female sex were associated with reduced vaccine uptake. Healthcare workers in non-clinical roles also had reduced vaccine uptake. These findings should inform vaccination strategies across healthcare settings and target populations with reduced vaccine uptake directly, in particular young, female, and non-clinical healthcare workers, both for SARS-CoV-2 and other healthcare-associated vaccine-preventable infections.

Invasive Aspergillosis in the Intensive Care Unit.

Invasive pulmonary aspergillosis (IPA) is a serious condition resulting in significant mortality and morbidity among patients in intensive care units (ICUs). There is a growing number of at-risk patients for this condition with the increasing use of immunosuppressive therapies. The diagnosis of IPA can be difficult in ICUs, and relies on integration of clinical, radiological, and microbiological features. In this review, we discuss patient populations at risk for IPA, as well as the diagnostic criteria employed. We review the fungal biomarkers used, as well as the challenges in distinguishing colonization with Aspergillus from invasive disease. We also address the growing concern of multidrug-resistant Aspergillosis and review the new and novel therapeutics which are in development to combat this.

Neuropsychological decrements in midlife type-2 diabetes are not associated with peripheral NLRP3 inflammasome responsiveness.

Midlife Type 2 Diabetes Mellitus (T2DM) is associated with an increased risk of Alzheimer Disease (AD) in later life, with altered inflammatory responses postulated as key pathological drivers. Previous studies have demonstrated increased responsiveness to NLR family pyrin domain containing 3 (NLRP3) inflammasome agonists, both in individuals with untreated T2DM in addition to those with established AD. We hypothesised that peripheral NLRP3 inflammasome responses may be altered during the early stages of T2DM-related cognitive dysfunction. Here, we assessed the relationship between NLPR3 responses in peripheral blood mononuclear cells (including to Aß-42, the putative pathogenic protein in AD) and neuropsychological performance in uncomplicated midlife T2DM to identify early signatures of immune dysregulation which may predispose to later cognitive decline. We recruited a cross-sectional cohort of middle-aged adults with uncomplicated T2DM and matched Healthy Controls (HCs) for comprehensive neuropsychological assessment and in vitro PBMC responses to a range of NLRP3 agonists were assessed. T2DM was associated with subtle decrements on neuropsychological tests of delayed memory and executive function (both p<0.05). Overall, there were no differences between T2DM and HCs in immune responses induced by NLRP3 agonists. Further, we observed no relationship between the subtle neuropsychological decrements observed in T2DM and PBMC responsiveness to NLRP3 agonists. Our data suggests that peripheral NLRP3 inflammasome response dysregulation may not play a role in the early stages of cognitive dysfunction in midlife T2DM. Further longitudinal studies are warranted to examine the contribution of peripheral NLRP3 responses towards disease pathology and as cognitive decline accelerates in T2DM.

A changing demographic - Ten years of HIV care.

We aimed to benchmark the quality of care and describe characteristics of patients newly attending the HIV clinic at differing time points over the past 10 years, against the Infectious Disease Society of America HIV/AIDS performance measures. We performed a retrospective analysis of records for patients newly attending the HIV clinic in 2011, 2016 and 2018. There was an increase in male attendees in 2018 and 2016 compared to 2011 (88%, 88% vs. 59% p < .001), viral suppression rates were 97%, 83% and 99% (p < .001), respectively. We observed an increase in patients of South American origin over time. Acquisition risk changed, with increased proportion of MSM (24% in 2011 vs 78% in 2018, p < .001), lower rates of heterosexual (20% in 2018 vs 48% in 2011, p < .001) and IDU transmission (1.5% in 2018 vs 24% in 2011, p < .001). There were lower rates of Chlamydia trachomatis and Neisseria gonorrhoeae testing in 2018 (72%, p < .001), compared to 2016 (84%) and 2011 (83%). Hepatitis B virus vaccination and pneumococcal vaccine rates are declining (p < .001). We demonstrate the changes in both ethnicity and risk of acquisition over time, high rates of antiretroviral therapy prescription and viral suppression, and highlight the importance of health prevention with sexual health screening and vaccination in this population.

Early IFNß secretion determines variable downstream IL-12p70 responses upon TLR4 activation.

The interleukin-12 (IL-12) family comprises the only heterodimeric cytokines mediating diverse functional effects. We previously reported a striking bimodal IL-12p70 response to lipopolysaccharide (LPS) stimulation in healthy donors. Herein, we demonstrate that interferon ß (IFNß) is a major upstream determinant of IL-12p70 production, which is also associated with numbers and activation of circulating monocytes. Integrative modeling of proteomic, genetic, epigenomic, and cellular data confirms IFNß as key for LPS-induced IL-12p70 and allowed us to compare the relative effects of each of these parameters on variable cytokine responses. Clinical relevance of our findings is supported by reduced IFNß-IL-12p70 responses in patients hospitalized with acute severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection or chronically infected with hepatitis C (HCV). Importantly, these responses are resolved after viral clearance. Our systems immunology approach defines a better understanding of IL-12p70 and IFNß in healthy and infected persons, providing insights into how common genetic and epigenetic variation may impact immune responses to bacterial infection.

Defective activation and regulation of type I interferon immunity is associated with increasing COVID-19 severity.

Host immunity to infection with SARS-CoV-2 is highly variable, dictating diverse clinical outcomes ranging from asymptomatic to severe disease and death. We previously reported reduced type I interferon in severe COVID-19 patients preceded clinical worsening. Further studies identified genetic mutations in loci of the TLR3- or TLR7-dependent interferon-I pathways, or neutralizing interferon-I autoantibodies as risk factors for development of COVID-19 pneumonia. Here we show in patient cohorts with different severities of COVID-19, that baseline plasma interferon α measures differ according to the immunoassay used, timing of sampling, the interferon α subtype measured, and the presence of autoantibodies. We also show a consistently reduced induction of interferon-I proteins in hospitalized COVID-19 patients upon immune stimulation, that is not associated with detectable neutralizing autoantibodies against interferon α or interferon ω. Intracellular proteomic analysis shows increased monocyte numbers in hospitalized COVID-19 patients but impaired interferon-I response after stimulation. We confirm this by ex vivo whole blood stimulation with interferon-I which induces transcriptomic responses associated with inflammation in hospitalized COVID-19 patients, that is not seen in controls or non-hospitalized moderate cases. These results may explain the dichotomy of the poor clinical response to interferon-I based treatments in late stage COVID-19, despite the importance of interferon-I in early acute infection and may guide alternative therapeutic strategies.

Sustained VWF-ADAMTS-13 axis imbalance and endotheliopathy in long COVID syndrome is related to immune dysfunction.

BACKGROUND: Prolonged recovery is common after acute SARS-CoV-2 infection; however, the pathophysiological mechanisms underpinning Long COVID syndrome remain unknown. VWF/ADAMTS-13 imbalance, dysregulated angiogenesis, and immunothrombosis are hallmarks of acute COVID-19. We hypothesized that VWF/ADAMTS-13 imbalance persists in convalescence together with endothelial cell (EC) activation and angiogenic disturbance. Additionally, we postulate that ongoing immune cell dysfunction may be linked to sustained EC and coagulation activation. PATIENTS AND METHODS: Fifty patients were reviewed at a minimum of 6 weeks following acute COVID-19. ADAMTS-13, Weibel Palade Body (WPB) proteins, and angiogenesis-related proteins were assessed and clinical evaluation and immunophenotyping performed. Comparisons were made with healthy controls (n = 20) and acute COVID-19 patients (n = 36). RESULTS: ADAMTS-13 levels were reduced (p = 0.009) and the VWF-ADAMTS-13 ratio was increased in convalescence (p = 0.0004). Levels of platelet factor 4 (PF4), a putative protector of VWF, were also elevated (p = 0.0001). A non-significant increase in WPB proteins Angiopoietin-2 (Ang-2) and Osteoprotegerin (OPG) was observed in convalescent patients and WPB markers correlated with EC parameters. Enhanced expression of 21 angiogenesis-related proteins was observed in convalescent COVID-19. Finally, immunophenotyping revealed significantly elevated intermediate monocytes and activated CD4+ and CD8+ T cells in convalescence, which correlated with thrombin generation and endotheliopathy markers, respectively. CONCLUSION: Our data provide insights into sustained EC activation, dysregulated angiogenesis, and VWF/ADAMTS-13 axis imbalance in convalescent COVID-19. In keeping with the pivotal role of immunothrombosis in acute COVID-19, our findings support the hypothesis that abnormal T cell and monocyte populations may be important in the context of persistent EC activation and hemostatic dysfunction during convalescence.

Severe COVID-19 is characterised by inflammation and immature myeloid cells early in disease progression.

SARS-CoV-2 infection causes a wide spectrum of disease severity. Identifying the immunological characteristics of severe disease and the risk factors for their development are important in the management of COVID-19. This study aimed to identify and rank clinical and immunological features associated with progression to severe COVID-19 in order to investigate an immunological signature of severe disease. One hundred and eight patients with positive SARS-CoV-2 PCR were recruited. Routine clinical and laboratory markers were measured, as well as myeloid and lymphoid whole-blood immunophenotyping and measurement of the pro-inflammatory cytokines IL-6 and soluble CD25. All analysis was carried out in a routine hospital diagnostic laboratory. Univariate analysis demonstrated that severe disease was most strongly associated with elevated CRP and IL-6, loss of DLA-DR expression on monocytes and CD10 expression on neutrophils. Unbiased machine learning demonstrated that these four features were strongly associated with severe disease, with an average prediction score for severe disease of 0.925. These results demonstrate that these four markers could be used to identify patients developing severe COVID-19 and allow timely delivery of therapeutics.