Antibody-Dependent Enhancement (ADE) and the role of complement system in disease pathogenesis.

Antibody-dependent enhancement (ADE) has been associated with severe disease outcomes in several viral infections, including respiratory infections. In vitro and in vivo studies showed that antibody-response to SARS-CoV and MERS-CoV could exacerbate infection via ADE. Recently in SARS CoV-2, the in vitro studies and structural analysis shows a risk of disease severity via ADE. This phenomenon is partially attributed to non-neutralizing antibodies or antibodies at sub-neutralizing levels. These antibodies result in antigen-antibody complexes' deposition and propagation of a chronic inflammatory process that destroys affected tissues. Further, antigen-antibody complexes may enhance the internalization of the virus into cells through the Fc gamma receptor (FcγR) and lead to further virus replication. Thus, ADE occur via two mechanisms; 1. Antibody mediated replication and 2. Enhanced immune activation. Antibody-mediated effector functions are mainly driven by complement activation, and the first complement in the cascade is complement 1q (C1q) which binds to the virus-antibody complex. Reports say that deficiency in circulating plasma levels of C1q, an independent predictor of mortality in high-risk patients, including diabetes, is associated with severe viral infections. Complement mediated ADE is reported in several viral infections such as dengue, West Nile virus, measles, RSV, Human immunodeficiency virus (HIV), and Ebola virus. This review discusses ADE in viral infections and the in vitro evidence of ADE in coronaviruses. We outline the mechanisms of ADE, emphasizing the role of complements, especially C1q in the outcome of the enhanced disease.

Adding colchicine to tocilizumab in hospitalized patients with severe COVID-19 pneumonia: An open-label randomized controlled trial.

INTRODUCTION: Colchicine acts upstream in the cytokines cascade by inhibiting the nod-like receptor protein 3 (NLRP3) inflammasome while interleukin 6 (IL-6) receptor antagonists, such as tocilizumab, block the end result of the cytokines cascade. Hence, adding colchicine to tocilizumab with the aim of blocking the early and end products of the cytokines cascade, might reduce the risk of developing cytokine storm. METHODS AND ANALYSIS: We aim to conduct an open-label randomized controlled trial to evaluate the efficacy and safety of adding colchicine to tocilizumab among patients with severe COVID-19 pneumonia to reduce the rate of invasive mechanical ventilation and mortality. We will include patients with severe COVID-19 pneumonia who received tocilizumab according to our local guidelines. Enrolled patients will be then randomized in 1:1 to colchicine versus no colchicine. Patients will be followed up for 30 days. The primary outcome is the rate of invasive mechanical ventilation and will be determined using Cox proportional hazard model. DISCUSSION: Given colchicine's ease of use, low cost, good safety profile, and having different anti-inflammatory mechanism of action than other IL-6 blockade, colchicine might serve as a potential anti-inflammatory agent among patients with severe COVID-19 pneumonia. This study will provide valuable insights on the use of colchicine in severe COVID-19 when added to IL-6 antagonists. ETHICS AND DISSEMINATION: The Medical Research Center and Institutional Review Board at Hamad Medical Corporation in Qatar approved the study protocol (MRC-01-21-299). Results of the analysis will be submitted for publication in a peer-reviewed journal.

Effectiveness of the neutralizing antibody sotrovimab among high-risk patients with mild-to-moderate SARS-CoV-2 in Qatar.

OBJECTIVES: To estimate the real-world effectiveness of sotrovimab against severe, critical, or fatal COVID-19 in Qatar at a time in which most SARS-CoV-2 incidences occurred due to the BA.2 Omicron subvariant. METHODS: We conducted a matched case-control study among all individuals eligible for sotrovimab treatment per United States Food and Drug Administration guidelines in the resident population of Qatar. The odds of progression to severe forms of COVID-19 were compared in cases (treatment group) versus controls (eligible patients who opted not to receive the treatment). Subgroup analyses were conducted. RESULTS: A total of 3364 individuals were eligible for sotrovimab treatment during the study period, of whom 519 individuals received the treatment, whereas the remaining 2845 constituted the controls. The adjusted odds ratio of disease progression to severe, critical, or fatal COVID-19 comparing the treatment group to the control group was 2.67 (95% confidence interval 0.60-11.91). In the analysis including only the subgroup of patients at higher risk of severe forms of COVID-19, the adjusted odds ratio was 0.65 (95% confidence interval 0.17-2.48). CONCLUSION: There was no evidence for a protective effect of sotrovimab in reducing COVID-19 severity in a setting dominated by the BA.2 subvariant.

Favipiravir for the treatment of coronavirus disease 2019 pneumonia; a propensity score-matched cohort study.

We retrospectively investigated the clinical outcomes of favipiravir in patients with COVID-19 pneumonia. Patients who between 23 May 2020 and 18 July 2020 received ≥ 24 h of favipiravir were assigned to the favipiravir group, while those who did not formed the non-favipiravir group. The primary outcome was 28-day clinical improvement, defined as two-category improvement from baseline on an 8-point ordinal scale. Propensity scores (PS) for favipiravir therapy were used for 1:1 matching. The unmatched cohort included 1493 patients, of which 51.7% were in the favipiravir group, and 48.3% were not receiving supplemental oxygen at baseline. Significant baseline differences between the two unmatched groups existed, but not between the PS-matched groups (N = 774). After PS-matching, there were no significant differences between the two groups in the proportion with 28-day clinical improvement (93.3% versus 92.8%, P 0.780), or 28-day all-cause mortality (2.1% versus 3.1%, P 0.360). Favipiravir was associated with more viral clearance by day 28 (79.8% versus 64.1%, P < 0.001). Adverse events were common in both groups, but the 93.9% were Grades 1-3. Favipiravir therapy for COVID-19 pneumonia is well tolerated but is not associated with an increased likelihood of clinical improvement or reduced all-cause mortality by 28 days.

COVID-19 disease severity in persons infected with the Omicron variant compared with the Delta variant in Qatar.

Background: Understanding the disease severity associated with the Omicron variant of the SARS-CoV-2 virus is important in determining appropriate management strategies at the individual and population levels. We determined the severity of SARS-CoV-2 infection in persons infected with the Omicron vs the Delta variant. Methods: We identified individuals with SARS-CoV-2 infection with Delta and propensity-score matched controls with Omicron variant infection from the National COVID-19 Database in Qatar. We excluded temporary visitors to Qatar, those with a prior documented infection, those ≤18 years old, and those with <14 days of follow up after the index test positive date. We determined the rates of admission to the hospital, admission to intensive care unit, mechanical ventilation, or death among those infected with the Delta or Omicron variants. Results: Among 9763 cases infected with the Delta variant and 11 310 cases infected with the Omicron variant, we identified 3926 propensity-score matched pairs. Among 3926 Delta infected, 3259 (83.0%) had mild, 633 (16.1%) had moderate and 34 (0.9%) had severe/critical disease. Among 3926 Omicron infected, 3866 (98.5%) had mild, 59 (1.5%) had moderate, and only 1 had severe/critical disease (overall P < 0.001). Factors associated with less moderate or severe/critical disease included infection with Omicron variant (aOR = 0.06; confidence interval (CI) = 0.05-0.09) and vaccination including a booster (aOR = 0.30; 95% CI = 0.09-0.99). Conclusions: Omicron variant infection is associated with significantly lower severity of disease compared with the Delta variant. Vaccination continues to offer strong protection against severe/critical disease.

Remdesivir for patients with Coronavirus disease 2019 pneumonia requiring high oxygen support.

BACKGROUND: Treatment options for patients with critical Coronavirus Disease 2019 (COVID-19) are limited. This study aimed to describe the clinical characteristics and outcomes associated with remdesivir therapy in patients with COVID-19 who require non-invasive (NIV) ventilation or invasive mechanical ventilation (IMV). METHODS: Data were retrospectively extracted for adults with COVID-19 confirmed using polymerase chain reaction (PCR) between August 1, 2020 and January 28, 2021 who received ≥ 48 hours of remdesivir therapy while on NIV or IMV. Clinical improvement was defined as two-category improvement on an eight-point ordinal severity scale. RESULTS: A total of 133 individuals were included, of which 114 (85.7%) were on NIV and 19 (14.3%) were on IMV at the time of remdesivir initiation. The majority of the patients were males (62.4%), and the median age was 56 years. All the patients received concomitant dexamethasone therapy. Remdesivir treatment was commenced after a median of 7 days from onset of symptoms and was continued for a median of 5 days. Clinical improvement within 28 days was achieved in 101 patients (75.9%); among which, 78.1% and 63.2% were subjected to baseline NIV and IMV, respectively. Among the 11 (8.3%) patients who died of any cause by day 28, 9 (7.9%) and 2 (10.5%) were subjected to baseline NIV and IMV, respectively. The most frequent adverse events were sinus bradycardia (21, 13.1%) and alanine transaminase increase (18, 11.3%). Almost all adverse events were classified as Grades 1-3. CONCLUSION: The use of remdesivir in combination with systemic corticosteroids is associated with high recovery rates and low all-cause mortality in patients with COVID-19 pneumonia who require NIV or IMV. The results need confirmation from clinical trials of appropriate design and size.

Coronavirus Disease 2019 Disease Severity in Children Infected With the Omicron Variant.

SHORT SUMMARY: Severe acute respiratory syndrome coronavirus 2 infection from the Omicron variant in children/adolescents is less severe than infection from the Delta variant. Those 6 to <18 years also have less severe disease than those <6 years old. BACKGROUND: There are limited data assessing coronavirus 2019 (COVID-19) disease severity in children/adolescents infected with the Omicron variant. METHODS: We identified children and adolescents <18 years of age with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection with Delta and propensity score-matched controls with Omicron variant infection from the National COVID-19 Database in Qatar. Primary outcome was disease severity, determined by hospital admission, admission to the intensive care unit (ICU), or mechanical ventilation within 14 days of diagnosis, or death within 28 days. RESULTS: Among 1735 cases with Delta variant infection between 1 June and 6 November 2021, and 32 635 cases with Omicron variant infection between 1 January and 15 January 2022, who did not have prior infection and were not vaccinated, we identified 985 propensity score-matched pairs. Among those who were Delta infected, 84.2% had mild, 15.7% had moderate, and 0.1% had severe/critical disease. Among those who were Omicron infected, 97.8% had mild, 2.2% had moderate, and none had severe/critical disease (P < .001). Omicron variant infection (vs Delta) was associated with significantly lower odds of moderate or severe/critical disease (adjusted odds ratio [AOR], 0.12; 95% confidence interval [CI], .07-.18). Those aged 6-11 and 12 to <18 years had lower odds of developing moderate or severe/critical disease compared with those younger than age 6 years (aOR, 0.47; 95% CI, .33-.66 for 6-11 year olds; aOR, 0.45; 95% CI, .21-.94 for 12 to <18 year olds). CONCLUSIONS: Omicron variant infection in children/adolescents is associated with less severe disease than Delta variant infection as measured by hospitalization rates and need for ICU care or mechanical ventilation. Those 6 to <18 years of age also have less severe disease than those <6 years old.

Clinical outcomes of post-renal transplant patients with COVID-19 infection in the ICU: A single-center case series.

Most of the post-renal transplant patients are taking immunosuppressive medications, including calcineurin inhibitors, anti-proliferative agents, and steroids. This case series highlights the clinical characteristics and outcomes of eight post-renal transplant patients with severe COVID-19 infection admitted to the intensive care unit.

Clinical characteristics and risk factors for COVID-19-associated Candidemia.

Patients with COVID-19-associated candidemia (CAC) in an intensive care unit (ICU) were matched 1:2 with those without candidemia, based on ICU admission date and length of stay in ICU being at least equal to that before candidemia in the corresponding case. The incidence rate of CAC was 2.34 per 1000 ICU days. Eighty cases could be matched to appropriate controls. In the multivariate conditional logistic regression analysis, age (P 0.001), and sequential organ failure assessment score (P 0.046) were the only risk factors independently associated with CAC. Tocilizumab and corticosteroids therapy were not independently associated with candidemia. LAY SUMMARY: In COVID-19 patients who need medical care in an intensive care unit, the risk of developing bloodstream Candida infection is higher in older patients and in those who have a more severe critical illness. Treatment with steroids or tocilizumab does not seem to affect the risk of candida bloodstream infection in these patients.

Coronavirus disease 2019 in solid organ transplant recipients in the setting of proactive screening and contact tracing of Qatar.

BACKGROUND: Clinical data on Coronavirus Disease 2019 (COVID-19) in solid organ transplant (SOT) recipients are limited. We herein report the initial clinical experience with COVID-19 in SOT recipients in Qatar. METHODS: All SOT recipients with laboratory-confirmed COVID-19 up to May 23, 2020 were included. Demographic and clinical data were extracted retrospectively from the hospital's electronic health records. Categorical data are presented as frequency and percentages, while continuous variables are summarized as medians and ranges. RESULTS: Twenty-four SOT recipients with COVID-19 were identified (kidney 16, liver 6, heart 1, and liver and kidney 1). Organ transplantation preceded COVID-19 by a median of 60 months (range 1.7-184). The median age was 57 years (range 24-72), and 9 (37.5%) transplant recipients were females. Five (21%) asymptomatic patients were diagnosed through proactive screening. For the rest, fever (15/19) and cough (13/19) were the most frequent presenting symptoms. Five (20.8%) patients required invasive mechanical ventilation in the intensive care unit (ICU). Eleven (46%) patients developed acute kidney injury, including three in association with drug-drug interactions involving investigational COVID-19 therapies. Maintenance immunosuppressive therapy was modified in 18 (75%) patients, but systemic corticosteroids were not discontinued in any. After a median follow-up of 226 days (26-272), 20 (83.3%) patients had been discharged home, 2 (8.3%) were still hospitalized, 1 (4.2%) was still in the ICU, and 1 (4.2%) had died. CONCLUSIONS: Our results suggest that asymptomatic COVID-19 is possible in SOT recipients and that overall outcomes are not uniformly worse than those in the general population. The results require confirmation in large, international cohorts.

The initial impact of a national BNT162b2 mRNA COVID-19 vaccine rollout.

OBJECTIVE: This study examined the initial impact of a national BNT162b2 vaccine rollout on SARS-CoV-2 infections in Qatar. METHODS: All individuals who had completed ≥14 days of follow-up by 16 March 2021 after receiving the BNT162b2 vaccine were included. This study calculated incidence rates (IR) and their 95% confidence intervals (CI) during days 1-7, 8-14, 15-21, 22-28, and >28 days post-vaccination. Poisson regression was used to calculate incidence rate ratios (IRR) relative to the first 7-day post-vaccination period. RESULTS: A total of 199,219 individuals with 6,521,124 person-days of follow-up were included. SARS-CoV-2 infection was confirmed in 1877 (0.9%), of which 489 (26.1%) were asymptomatic and 123 (6.6%) required oxygen support. The median time from first vaccination to SARS-CoV-2 confirmation was 11.9 days (IQR 7.7-18.2). Compared with the first 7-day post-vaccination period, SARS-CoV-2 infections were lower by 65.8-84.7% during 15-21, 22-28, and >28 days (P < 0.001 for each). For severe COVID-19, the incidence rates were 75.7-93.3% lower during the corresponding time periods (P < 0.001 for each). CONCLUSION: The results were consistent with an early protective effect of BNT162b2 vaccine against all degrees of SARS-CoV-2 severity.

Convalescent plasma for the treatment of patients with severe coronavirus disease 2019: A preliminary report.

BACKGROUND: The role of convalescent plasma therapy for patients with coronavirus disease 2019 (COVID-19) is unclear. METHODS: We retrospectively compared outcomes in a cohort of critical COVID-19 patients who received standard care (SC Group) and those who, in addition, received convalescent plasma (CP Group). RESULTS: In total, 40 patients were included in each group. The median patient age was 53.5 years (interquartile range [IQR] 42-60.5), and the majority of patients required invasive ventilation (69, 86.2%). Plasma was harvested from donors after a median of 37 days (IQR 31-46) from the first positive severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) polymerase chain reaction (PCR) result and 26 days (IQR 21-32) after documented viral clearance; it was administered after a median of 10 days (IQR 9-10) from the onset of symptoms and 2.5 days (IQR 2-4) from admission to intensive care unit. The primary endpoint of improvement in respiratory support status within 28 days was achieved in 26 patients (65%) in the SC Group and 31 patients (77.5%) in the CP Group (p = .32). The 28-day all-cause mortality (12.5% vs. 2.5%; p = .22) and viral clearance (65% vs. 55%; p = .49) were not significantly different between the two groups. Convalescent plasma was not significantly associated with the primary endpoint (adjusted hazard ratio 0.87; 95% confidence interval 0.51-1.49; p = .62). Adverse events were balanced between the two study groups. CONCLUSION: In severe COVID-19, convalescent plasma therapy was not associated with clinical benefits. Randomized trials are required to confirm our findings.

The first consecutive 5000 patients with Coronavirus Disease 2019 from Qatar; a nation-wide cohort study.

BACKGROUND: There are limited data on Coronavirus Disease 2019 (COVID-19) outcomes at a national level, and none after 60 days of follow up. The aim of this study was to describe national, 60-day all-cause mortality associated with COVID-19, and to identify risk factors associated with admission to an intensive care unit (ICU). METHODS: This was a retrospective cohort study including the first consecutive 5000 patients with COVID-19 in Qatar who completed 60 days of follow up by June 17, 2020. The primary outcome was all-cause mortality at 60 days after COVID-19 diagnosis. In addition, we explored risk factors for admission to ICU. RESULTS: Included patients were diagnosed with COVID-19 between February 28 and April 17, 2020. The majority (4436, 88.7%) were males and the median age was 35 years [interquartile range (IQR) 28-43]. By 60 days after COVID-19 diagnosis, 14 patients (0.28%) had died, 10 (0.2%) were still in hospital, and two (0.04%) were still in ICU. Fatal COVID-19 cases had a median age of 59.5 years (IQR 55.8-68), and were mostly males (13, 92.9%). All included pregnant women (26, 0.5%), children (131, 2.6%), and healthcare workers (135, 2.7%) were alive and not hospitalized at the end of follow up. A total of 1424 patients (28.5%) required hospitalization, out of which 108 (7.6%) were admitted to ICU. Most frequent co-morbidities in hospitalized adults were diabetes (23.2%), and hypertension (20.7%). Multivariable logistic regression showed that older age [adjusted odds ratio (aOR) 1.041, 95% confidence interval (CI) 1.022-1.061 per year increase; P < 0.001], male sex (aOR 4.375, 95% CI 1.964-9.744; P < 0.001), diabetes (aOR 1.698, 95% CI 1.050-2.746; P 0.031), chronic kidney disease (aOR 3.590, 95% CI 1.596-8.079, P 0.002), and higher BMI (aOR 1.067, 95% CI 1.027-1.108 per unit increase; P 0.001), were all independently associated with increased risk of ICU admission. CONCLUSIONS: In a relatively younger national cohort with a low co-morbidity burden, COVID-19 was associated with low all-cause mortality. Independent risk factors for ICU admission included older age, male sex, higher BMI, and co-existing diabetes or chronic kidney disease.

Fatal Coronavirus Disease 2019-associated Pulmonary Aspergillosis; A Report of Two Cases and Review of the Literature.

Coronavirus Disease 2019 (COVID-19)-associated pulmonary aspergillosis is an emerging entity. We report two fatal cases of putative COVID-19-associated pulmonary aspergillosis. Both cases were diagnosed on the basis of respiratory tract cultures yielding Aspergillus species and otherwise unexplained clinical and radiological deterioration. Existing published literature on COVID-19-associated pulmonary aspergillosis indicate poor outcomes and high mortality. CAPA should be considered in patients with critical COVID-19 who have unexplained progressive respiratory failure despite optimized supportive care. Diagnostic work-up should be initiated as early as possible and should ideally include fungal cultures, galactomannan detection and Aspergillus PCR on tracheal aspirates or broncho-alveolar lavage fluid. Empiric systemic antifungal therapy may be justified in selected cases, pending diagnostic work up results. Large, multi-center studies are required to further understand the pathogenesis of invasive aspergillosis in COVID-19, and the optimal diagnostic and treatment strategies.

Tocilizumab for the treatment of severe coronavirus disease 2019.

Tocilizumab, an interleukin-6 inhibitor, may ameliorate the inflammatory manifestations associated with severe coronavirus disease 2019 (COVID-19) and thus improve clinical outcomes. This was a retrospective review of patients with laboratory-confirmed severe COVID-19 who received tocilizumab and completed 14 days of follow up. Twenty-five patients were included, median age was 58 years (interquartile range, 50-63) and the majority were males (92%). Co-morbidities included diabetes mellitus (48%), chronic kidney disease (16%), and cardiovascular disease (12%). Fever (92%), cough (84%), and dyspnea (72%) were the commonest presenting symptoms. All patients received at least two concomitant investigational antiviral agents. Median oral temperature was on day 1, 3, and 7 was 38.0°C, 37.3°C (P = .043), and 37.0°C (P = .064), respectively. Corresponding median C-reactive protein was 193 and 7.9 mg/L (P < .0001) and <6 mg/L (P = .0001). Radiological improvement was noted in 44% of patients by day 7% and 68% by day 14. Nine patients (36%) were discharged alive from intensive care unit and three (12%) died. The proportion of patients on invasive ventilation declined from (84%) at the time of tocilizumab initiation to 60% on day 7 (P = .031) and 28% on day 14 (P = .001). The majority (92%) of patients experienced at least one adverse event. However, it is not possible to ascertain which adverse events were directly related to tocilizumab therapy. In patients with severe COVID-19, tocilizumab was associated with dramatic decline in inflammatory markers, radiological improvement and reduced ventilatory support requirements. Given the study's limitations, the results require assessment in adequately powered randomized controlled trials.