SARS-CoV-2 variants of concern (VOCs) have emerged worldwide, with implications on the spread of the pandemic. Characterizing the cross-reactivity of antibodies against these VOCs is necessary to understand the humoral response of non-hospitalized individuals previously infected with SARS-CoV-2, a population that remains understudied. Thirty-two SARS-CoV-2-positive (PCR-confirmed) and non-hospitalized Canadian adults were enrolled 14–21 days post-diagnosis in 2020, before the emergence of the B.1.351 (also known as Beta), B.1.617.2 (Delta) and P.1 (Gamma) VOCs. Sera were collected 4 and 16 weeks post-diagnosis. Antibody levels and pseudo-neutralization of the ectodomain of SARS-CoV-2 spike protein/human ACE-2 receptor interaction were analyzed with native, B.1.351, B.1.617.2 and P.1 variant spike proteins. Despite a lower response observed for the variant spike proteins, we report evidence of a sustained humoral response against native, B.1.351, B.1.617.2 and P.1 variant spike proteins among non-hospitalized Canadian adults. Furthermore, this response inhibited the interaction between the spike proteins from the different VOCs and ACE-2 receptor for ≥ 16 weeks post-diagnosis, except for individuals aged 18–49 years who showed no inhibition of the interaction between B.1.617.1 or B.1.617.2 spike and ACE-2. Interestingly, the affinity (KD) measured between the spike proteins (native, B.1.351, B.1.617.2 and P.1) and antibodies elicited in sera of infected and vaccinated (BNT162b2 and ChAdOx1 nCoV-19) individuals was invariant. Relative to sera from vaccine-naïve (and previously infected) individuals, sera from vaccinated individuals had higher antibody levels (as measured with label-free SPR) and more efficiently inhibited the spike–ACE-2 interactions, even among individuals aged 18–49 years, showing the effectiveness of vaccination.

Aims:The overall cost and health-related quality of life (HRQoL) associated with current treatments for chronic kidney disease (CKD)-related anemia are not well characterized. A systematic literature review (SLR) was conducted on the costs and HRQoL associated with current treatments for CKD-related anemia among dialysis-dependent (DD) patients. Materials and methods: The authors searched the Cochrane Library, MEDLINE, EMBASE, NHS EED, and NHS HTA for English-language publications. Original studies published between January 1, 2000 and March 17, 2017 meeting the following criteria were included: adult population; study focus was CKD-related anemia; included results on patients receiving iron supplementation, red blood cell transfusion, or erythropoiesis stimulating agents (ESAs); reported results on HRQoL and/or costs. Studies which included patients with DD-CKD, did not directly compare different treatments, and had designs relevant to the objective were retained. HRQoL and cost outcomes, including healthcare resource utilization (HRU), were extracted and summarized in a narrative synthesis. Results: A total of 1,625 publications were retrieved, 15 of which met all inclusion criteria. All identified studies included ESAs as a treatment of interest. Two randomized controlled trials reported that ESA treatment improves HRQoL relative to placebo. Across eight studies comparing HRQoL of patients achieving high vs low hemoglobin (Hb) targets, aiming for higher Hb targets with ESAs generally led to modest HRQoL improvements. Two studies reported that ESA-treated patients had lower costs and HRU compared to untreated patients. One study found that aiming for higher vs lower Hb targets led to reduced HRU, while two other reported that this led to a reduction in cost-effectiveness. Limitations: Heterogeneity of study designs and outcomes; a meta-analysis could not be performed. Conclusions: ESA-treated patients undergoing dialysis incurred lower costs, lower HRU, and had better HRQoL relative to ESA-untreated patients. However, treatment to higher Hb targets led to modest HRQoL improvements compared to lower Hb targets.

BackgroundThe cost and health-related quality of life (HRQoL) burden associated with treatments for anaemia of chronic kidney disease (CKD) is not well characterized among non-dialysis-dependent (NDD) patients.ObjectiveOur objective was to review the literature on costs and HRQoL associated with current treatments for anaemia of CKD among NDD patients.MethodsThe Cochrane Library, MEDLINE, Embase, NHS EED, and NHS HTA databases were searched for original studies published in English between 1 January 2000 and 17 March 2017. The following inclusion criteria were applied: adult population; primary focus was anaemia of CKD; patients received iron supplementation, red blood cell transfusion, or erythropoiesis-stimulating agents (ESAs); and reported results on HRQoL and/or costs. Studies that included NDD patients, did not compare different treatments, and had relevant designs were retained. HRQoL and cost outcomes were summarized in a narrative synthesis.ResultsIn total, 16 studies met the inclusion criteria: six randomized controlled trials, four prospective single-arm trials, three retrospective studies, one prospective observational study, one simulation study, and one cross-sectional survey. All included ESAs. Treatment of anaemia (compared with no treatment) was associated with HRQoL improvements in five of six studies and lower costs in four of four studies. Treatment aiming for higher haemoglobin targets (compared with lower targets) resulted in modest HRQoL improvements, higher healthcare resource utilization (HRU), and higher costs.ConclusionsIn NDD patients, untreated anaemia of CKD leads to higher costs, higher HRU, and lower HRQoL compared with initiating anaemia treatment. Relative to aiming for lower haemoglobin targets with ESAs, higher targets conferred modest HRQoL improvements and were associated with higher HRU.

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Background: Serosurveys have been key to public health decision-making since the beginning of the SARS-CoV-2 pandemic. However, emerging evidence suggests that vaccination decreases the sensitivity of anti-nucleocapsid (N) serologies, making them less reliable to assess recently-acquired infections. We therefore developed and tested a new approach based on the ratio of the anti-N absorbance of longitudinal samples to overcome this limitation. Methods: Previously vaccinated repeat plasma donors infected between 12/15/2021 and 03/20/2022 were included if they made at least one donation pre-infection (reference sample) and one donation post-infection (test sample). All samples were tested using an in-house anti-N ELISA, the sensitivity of which had been determined prior to the vaccination era. Instead of using the previously determined signal cut-off (conventional approach), seropositivity was determined based on the ratio between the anti-N absorbance of the test and reference samples. The approach was tested in a real-world setting during three cross-sectional serosurveys carried out among plasma donors in Québec (Canada) from 01/17/2022 to 03/18/2022. Results: Using a cut-off ratio of 1.5, this approach had a sensitivity of 95.2% among the 248 previously vaccinated and infected donors compared with 63.3% for the conventional approach. When tested in a real-world setting, the ratio-based approach yielded an adjusted seroprevalence of 27.4% (95% confidence interval [CI]=23.8%-30.9%) at the latest time point considered, compared to 15.1% (95% CI=12.2%-18.0%) for the conventional approach. Conclusions: This article describes a new and highly-sensitive approach that captures a significantly greater proportion of vaccinated individuals with a recent history of SARS-CoV-2 infection.