Molecular assays on nasopharyngeal swabs remain the cornerstone of COVID-19 diagnostics. The high technicalities of nasopharyngeal sampling and molecular assays, as well as scarce resources of ...reagents, limit our testing capabilities. Several strategies failed, to date, to fully alleviate this testing process (e.g. saliva sampling or antigen testing on nasopharyngeal samples). We assessed the clinical performances of SARS-CoV-2 nucleocapsid antigen (N-antigen) ELISA detection in serum or plasma using the COVID-19 Quantigene® (AAZ, France) assay.
Performances were determined on 63 serum samples from 63 non-COVID patients and 227 serum samples (165 patients) from the French COVID and CoV-CONTACT cohorts with RT-PCR-confirmed SARS-CoV-2 infection, including 142 serum samples (114 patients) obtained within 14 days after symptom onset.
Specificity was 98.4% (95% CI 95.3–100). Sensitivity was 79.3% overall (180/227, 95% CI, 74.0–84.6) and 93.0% (132/142, 95% CI, 88.7–97.2) within 14 days after symptom onset. Ninety-one of the included patients had serum samples and nasopharyngeal swabs collected in the same 24 hr. Among those with high nasopharyngeal viral loads, i.e. Ct value below 30 and 33, only 1/50 and 4/67 tested negative for N-antigenaemia, respectively. Among those with a negative nasopharyngeal RT-PCR, 8/12 presented positive N-antigenaemia; the lower respiratory tract was explored for six of these eight patients, showing positive RT-PCR in five cases.
This is the first evaluation of a commercially available serum N-antigen detection assay. It presents a robust specificity and sensitivity within the first 14 days after symptoms onset. This approach provides a valuable new option for COVID-19 diagnosis, only requiring a blood draw and easily scalable in all clinical laboratories.
Abstract
Background
Humoral response to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) occurs within the first weeks after coronavirus disease 2019 (COVID-19). Those antibodies exert a ...neutralizing activity against SARS-CoV-2, whose evolution over time after COVID-19 as well as efficiency against novel variants are poorly characterized.
Methods
In this prospective study, sera of 107 patients hospitalized with COVID-19 were collected at 3 and 6 months postinfection. We performed quantitative neutralization experiments on top of high-throughput serological assays evaluating anti-spike (S) and anti-nucleocapsid (NP) immunoglobulin G (IgG).
Results
Levels of seroneutralization and IgG rates against the ancestral strain decreased significantly over time. After 6 months, 2.8% of the patients had a negative serological status for both anti-S and anti-NP IgG. However, all sera had a persistent and effective neutralizing effect against SARS-CoV-2. IgG levels correlated with seroneutralization, and this correlation was stronger for anti-S than for anti-NP antibodies. The level of seroneutralization quantified at 6 months correlated with markers of initial severity, notably admission to intensive care units and the need for mechanical invasive ventilation. In addition, sera collected at 6 months were tested against multiple SARS-CoV-2 variants and showed efficient neutralizing effects against the D614G, B.1.1.7, and P.1 variants but significantly weaker activity against the B.1.351 variant.
Conclusions
Decrease in IgG rates and serological assays becoming negative did not imply loss of neutralizing capacity. Our results indicate a sustained humoral response against the ancestral strain and the D614G, B.1.1.7, and P.1 variants for at least 6 months in patients previously hospitalized for COVID-19. A weaker protection was, however, observed for the B.1.351 variant.
Little is known on the association between clinical factors and coronavirus disease 2019 (COVID‐19) more than 15 days after diagnosis. We conducted a multicentric prospective cohort of COVID‐19 ...hospitalized patients to describe clinical, biological, and virological characteristics at hospital admission and over time, according to mortality up to Day 60 after admission. For the analysis of risk factors of survival, analyses assessing associations between mortality and demographic characteristics or comorbidities were performed using a Cox regression model. Between January 24 and March 15, 2020, 246 patients with reverse‐transcriptase polymerase chain reactions virologically confirmed COVID‐19 were enrolled. In multivariate analysis, mortality at Day 60 (n = 42 patients, 17.1% 95% confidence interval, 12.6–22.4) was associated with older age (adjusted hazard ratio aHR for age ≥ 65 years: 5.22 2.56–10.63, p < .001), gender (aHR for male: 2.97 1.47–5.99, p = .002), chronic pulmonary disease (aHR: 4.84 2.32–10.07, p < .001), obesity (aHR: 3.32 1.70–6.52, p < .001), and diabetes (aHR: 1.98 1.01–3.89, p = .048). The median nasopharyngeal viral load at admission was 6.4 log10 copies/ml and was associated with mortality regardless of clinical risk factors. Viral load decreased with time elapsed since symptoms onset. Our study confirmed that mortality was associated with clinical characteristics at admission. The viral load at admission was significantly lower in patients admitted late after the onset of symptoms in both dead and alive patients. Our results could improve earlier identification of patients with increased risk of mortality and adapted management.
Highlights
Older age, male gender, chronic pulmonary disease (not asthma), obesity, and diabetes were associated with mortality in COVID‐19 hospitalized patients.
Viral load at admission decreased with the time since symptom onset, with an association with mortality adjusted on clinical risk factors.
Abstract
Background
The composition of the digestive microbiota may be associated with outcome and infections in patients admitted to the intensive care unit (ICU). The dominance by opportunistic ...pathogens (such
as Enterococcus
) has been associated with death. However, whether this association remains all throughout the hospitalization are lacking.
Methods
We performed a single-center observational prospective cohort study in critically ill patients admitted with severe SARS-CoV-2 infection. Oropharyngeal and rectal swabs were collected at admission and then twice weekly until discharge or death. Quantitative cultures for opportunistic pathogens were performed on oropharyngeal and rectal swabs. The composition of the intestinal microbiota was assessed by 16S rDNA sequencing. Oropharyngeal and intestinal concentrations of opportunistic pathogens, intestinal richness and diversity were entered into a multivariable Cox model as time-dependent covariates. The primary outcome was death at day 90.
Results
From March to September 2020, 95 patients (765 samples) were included. The Simplified Acute Physiology Score 2
(
SAPS 2) at admission was 33 24; 50 and a Sequential Organ Failure Assessment score (SOFA score) at 6 4; 8. Day 90 all-cause mortality was 44.2% (42/95). We observed that the oropharyngeal and rectal concentrations of
Enterococcus
spp.,
Staphylococcus aureus
and
Candida
spp. were associated with a higher risk of death. This association remained significant after adjustment for prognostic covariates (age, chronic disease, daily antimicrobial agent use and daily SOFA score). A one-log increase in
Enterococcus
spp
.
,
S. aureus
and
Candida
spp. in oropharyngeal or rectal swabs was associated with a 17% or greater increase in the risk of death.
Conclusion
We found that elevated oropharyngeal/intestinal
Enterococcus
spp.
S. aureus
and
Candida
spp. concentrations, assessed by culture, are associated with mortality, independent of age, organ failure, and antibiotic therapy, opening prospects for simple and inexpensive microbiota-based markers for the prognosis of critically ill SARS-CoV-2 patients.
Purpose
Following a severe COVID-19 infection, a proportion of individuals develop prolonged symptoms. We investigated the immunological dysfunction that underlies the persistence of symptoms months ...after the resolution of acute COVID-19.
Methods
We analyzed cytokines, cell phenotypes, SARS-CoV-2 spike-specific and neutralizing antibodies, and whole blood gene expression profiles in convalescent severe COVID-19 patients 1, 3, and 6 months following hospital discharge.
Results
We observed persistent abnormalities until month 6 marked by (i) high serum levels of monocyte/macrophage and endothelial activation markers, chemotaxis, and hematopoietic cytokines; (ii) a high frequency of central memory CD4
+
and effector CD8
+
T cells; (iii) a decrease in anti-SARS-CoV-2 spike and neutralizing antibodies; and (iv) an upregulation of genes related to platelet, neutrophil activation, erythrocytes, myeloid cell differentiation, and RUNX1 signaling. We identified a “core gene signature” associated with a history of thrombotic events, with upregulation of a set of genes involved in neutrophil activation, platelet, hematopoiesis, and blood coagulation.
Conclusion
The lack of restoration of gene expression to a normal profile after up to 6 months of follow-up, even in asymptomatic patients who experienced severe COVID-19, signals the need to carefully extend their clinical follow-up and propose preventive measures.
Aims
The role of renin‐angiotensin‐aldosterone system (RAAS) blockers on the course of coronavirus disease 2019 (COVID‐19) is debated. We assessed the association between chronic use of RAAS blockers ...and mortality among inpatients with COVID‐19 and explored reasons for discrepancies in the literature.
Methods and results
We included adult hypertensive patients from a prospective nationwide cohort of 3512 inpatients with COVID‐19 up to June 30, 2020. Cox proportional hazard models with various adjustment or propensity weighting methods were used to estimate the hazard ratios (HR) of 30‐day mortality for chronic users versus non‐users of RAAS blockers. We analyzed data of 1160 hypertensive patients: 719 (62%) were male and 777 (67%) were older than 65 years. The main comorbidities were diabetes (n = 416, 36%), chronic cardiac disease (n = 401, 35%), and obesity (n = 340, 29%); 705 (61%) received oxygen therapy. We recorded 135 (11.6%) deaths within 30 days of diagnosis. We found no association between chronic use of RAAS blockers and mortality (unadjusted HR = 1.13, 95% CI 0.8–1.6; propensity inverse probability treatment weighted HR = 1.09 0.86‐1.39; propensity standardized mortality ratio weighted HR = 1.08 0.79–1.47). Our comprehensive review of previous studies highlighted that significant associations were mostly found in unrestricted populations with inappropriate adjustment, or with biased in‐hospital exposure measurement.
Conclusion
Our results do not support previous concerns regarding these drugs, nor a potential protective effect as reported in previous poorly designed studies and meta‐analyses. RAAS blockers should not be discontinued during the pandemic, while in‐hospital management of these drugs will be clarified by randomized trials. NCT04262921.
Abstract Background The ISARIC prospective multinational observational study is the largest cohort of hospitalized patients with COVID-19. We present relationships of age, sex, and nationality to ...presenting symptoms. Methods International, prospective observational study of 60 109 hospitalized symptomatic patients with laboratory-confirmed COVID-19 recruited from 43 countries between 30 January and 3 August 2020. Logistic regression was performed to evaluate relationships of age and sex to published COVID-19 case definitions and the most commonly reported symptoms. Results ‘Typical’ symptoms of fever (69%), cough (68%) and shortness of breath (66%) were the most commonly reported. 92% of patients experienced at least one of these. Prevalence of typical symptoms was greatest in 30- to 60-year-olds (respectively 80, 79, 69%; at least one 95%). They were reported less frequently in children (≤ 18 years: 69, 48, 23; 85%), older adults (≥ 70 years: 61, 62, 65; 90%), and women (66, 66, 64; 90%; vs. men 71, 70, 67; 93%, each P < 0.001). The most common atypical presentations under 60 years of age were nausea and vomiting and abdominal pain, and over 60 years was confusion. Regression models showed significant differences in symptoms with sex, age and country. Interpretation This international collaboration has allowed us to report reliable symptom data from the largest cohort of patients admitted to hospital with COVID-19. Adults over 60 and children admitted to hospital with COVID-19 are less likely to present with typical symptoms. Nausea and vomiting are common atypical presentations under 30 years. Confusion is a frequent atypical presentation of COVID-19 in adults over 60 years. Women are less likely to experience typical symptoms than men.
Abstract Background The ISARIC prospective multinational observational study is the largest cohort of hospitalized patients with COVID-19. We present relationships of age, sex, and nationality to ...presenting symptoms. Methods International, prospective observational study of 60 109 hospitalized symptomatic patients with laboratory-confirmed COVID-19 recruited from 43 countries between 30 January and 3 August 2020. Logistic regression was performed to evaluate relationships of age and sex to published COVID-19 case definitions and the most commonly reported symptoms. Results ‘Typical’ symptoms of fever (69%), cough (68%) and shortness of breath (66%) were the most commonly reported. 92% of patients experienced at least one of these. Prevalence of typical symptoms was greatest in 30- to 60-year-olds (respectively 80, 79, 69%; at least one 95%). They were reported less frequently in children (≤ 18 years: 69, 48, 23; 85%), older adults (≥ 70 years: 61, 62, 65; 90%), and women (66, 66, 64; 90%; vs. men 71, 70, 67; 93%, each P < 0.001). The most common atypical presentations under 60 years of age were nausea and vomiting and abdominal pain, and over 60 years was confusion. Regression models showed significant differences in symptoms with sex, age and country. Interpretation This international collaboration has allowed us to report reliable symptom data from the largest cohort of patients admitted to hospital with COVID-19. Adults over 60 and children admitted to hospital with COVID-19 are less likely to present with typical symptoms. Nausea and vomiting are common atypical presentations under 30 years. Confusion is a frequent atypical presentation of COVID-19 in adults over 60 years. Women are less likely to experience typical symptoms than men.
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