Objectives: To validate the diagnostic accuracy of a Euroimmun SARS-CoV-2 IgG and IgA immunoassay for COVID-19. Methods: In this unmatched (1:2) case-control validation study, we used sera of 181 laboratoryconfirmed SARS-CoV-2 cases and 326 controls collected before SARS-CoV-2 emergence. Diagnostic accuracy of the immunoassay was assessed against a whole spike protein-based recombinant immunofluorescence assay (rIFA) by receiver operating characteristic (ROC) analyses. Discrepant cases between ELISA and rIFA were further tested by pseudo-neutralization assay. Results: COVID-19 patients were more likely to be male and older than controls, and 50.3% were hospitalized. ROC curve analyses indicated that IgG and IgA had high diagnostic accuracies with AUCs of 0.990 (95% Confidence Interval [95%CI]: 0.983-0.996) and 0.978 (95%CI: 0.967-0.989), respectively. IgG assays outperformed IgA assays (p¼0.01). Taking an assessed 15% inter-assay imprecision into account, an optimized IgG ratio cutoff > 2.5 displayed a 100% specificity (95%CI: 99-100) and a 100% positive predictive value (95%CI: 96-100). A 0.8 cutoff displayed a 94% sensitivity (95%CI: 88-97) and a 97% negative predictive value (95%CI: 95-99). Substituting the upper threshold for the manufacturer's, improved assay performance, leaving 8.9% of IgG ratios indeterminate between 0.8-2.5. Conclusions: The Euroimmun assay displays a nearly optimal diagnostic accuracy using IgG against SARS-CoV-2 in patient samples, with no obvious gains from IgA serology. The optimized cutoffs are fit for rulein and rule-out purposes, allowing determination of whether individuals in our study population have

44Objectives: To validate the diagnostic accuracy of a Euroimmun SARS-CoV-2 IgG and IgA 45 immunoassay for Methods: In this unmatched (1:1) case-control validation study, we used sera of 181 laboratory-47

No abstract

Several SARS-CoV-2 variants of concern (VOC) are spreading rapidly in different regions of the world. The underlying mechanisms behind their transmission advantage remain unclear. We measured viral load in 950 individuals and found that infections with variant Alpha exhibit a higher viral load and longer viral shedding compared to non-VOC. We then used a transmission model to analyze the spread of variant Alpha in Geneva, Switzerland, and variant Beta in South Africa. We estimated that Alpha is either associated with a 37% (95% compatibility interval, CI: 25-63%) increase in transmissibility or a 51% (95% CI: 32-80%) increase of the infectious duration, or a combination of the two mechanisms. Assuming 50% immune evasion for Beta, we estimated a 23% (95% CI: 10-37%) increase in transmissibility or a 38% (95% CI: 15-78%) increase of the infectious duration for this variant. Beta is expected to outgrow Alpha in regions where the level of naturally acquired immunity from previously circulating variants exceeds 20% to 40%. Close monitoring of Alpha and Beta in regions with different levels of immunity will help to anticipate the global spread of these and future variants.

Background Persistent symptoms of SARS‐CoV‐2 are prevalent weeks to months following the infection. To date, it is difficult to disentangle the direct from the indirect effects of SARS‐CoV‐2, including lockdown, social, and economic factors. Objective The study aims to characterize the prevalence of symptoms, functional capacity, and quality of life at 12 months in outpatient symptomatic individuals tested positive for SARS‐CoV‐2 compared to individuals tested negative. Methods From 23 April to 27 July 2021, outpatient symptomatic individuals tested for SARS‐CoV‐2 at the Geneva University Hospitals were followed up 12 months after their test date. Results At 12 months, out of the 1447 participants (mean age 45.2 years, 61.2% women), 33.4% reported residual mild to moderate symptoms following SARS‐CoV‐2 infection compared to 6.5% in the control group. Symptoms included fatigue (16% vs. 3.1%), dyspnea (8.9% vs. 1.1%), headache (9.8% vs. 1.7%), insomnia (8.9% vs. 2.7%), and difficulty concentrating (7.4% vs. 2.5%). When compared to the control group, 30.5% of SARS‐CoV‐2 positive individuals reported functional impairment at 12 months versus 6.6%. SARS‐CoV‐2 infection was associated with the persistence of symptoms (adjusted odds ratio [aOR] 4.1; 2.60–6.83) and functional impairment (aOR 3.54; 2.16–5.80) overall, and in subgroups of women, men, individuals younger than 40 years, those between 40–59 years, and in individuals with no past medical or psychiatric history. Conclusion SARS‐CoV‐2 infection leads to persistent symptoms over several months, including in young healthy individuals, in addition to the pandemic effects, and potentially more than other common respiratory infections. Symptoms impact functional capacity up to 12 months post infection.