SARS-CoV-2 spike IgG titres up to 137 days following Comirnaty mRNA COVID-19 vaccination, Israel, February to May 2021.

BackgroundData regarding the long-term protection afforded by vaccination for the SARS-CoV-2 infection are essential for allocation of scarce vaccination resources worldwide.MethodsWe conducted a retrospective cohort study aimed at studying the kinetics of IgG antibodies against SARS-CoV-2 in COVID-19-naïve patients fully vaccinated with two doses of Comirnaty mRNA COVID-19 vaccine. Geometric mean concentrations (GMCs) of antibody levels were reported. Linear models were used to assess antibody levels after full vaccination and their decline over time.ResultsThe study included 4,740 patients and 5,719 serological tests. Unadjusted GMCs peaked 28-41 days after the first dose at 10,174 AU/mL (95% CI: 9,211-11,237) and gradually decreased but remained well above the positivity cut-off. After adjusting for baseline characteristics and repeated measurements, the antibodies half-life time was 34.1 days (95% CI: 33.1-35.2), and females aged 16-39 years with no comorbidities had antibody levels of 20,613 AU/mL (95% CI: 18,526-22,934) on day 28 post-first-dose. Antibody levels were lower among males (0.736 of the level measured in females; 95% CI: 0.672-0.806), people aged 40-59 (0.729; 95% CI: 0.649-0.818) and ≥ 60 years (0.452; 95% CI: 0.398-0.513), and patients having haematological (0.241; 95% CI: 0.190-0.306) or solid malignancies (0.757; 95% CI: 0.650-0.881), chronic kidney disease with glomerular filtration rate (GFR) ≥ 30 (0.434; 95% CI: 0.354-0.532) or with GFR < 30 mL/min (0.176; 95% CI: 0.109-0.287), and immunosuppression (0.273; 95% CI: 0.235-0.317). Body mass index, cardiovascular disease, congestive heart failure, chronic obstructive pulmonary disease, diabetes and inflammatory bowel diseases were not associated with antibody levels.ConclusionsVaccination with two doses resulted in persistently high levels of antibodies (≥ cut-off of 50 AU/mL) up to 137 days post-first-dose. Risk factors for lower antibody levels were identified.

Evaluating red blood cell distribution width from community blood tests as a predictor of hospitalization and mortality in adults with SARS-CoV-2: a cohort study.

BACKGROUND: Red blood cell distribution width (RDW) has been assessed during COVID-19 patient hospitalization, however, further research should be done to evaluate RDW from routine community blood tests, before infection, as a risk factor for COVID-19 related hospitalization and mortality. PATIENTS AND METHODS: RDW was measured as a predictor along with age, sex, chronic illnesses, and BMI in logistic regressions to predict hospitalization and mortality. Hospitalization and mortality odds ratios (ORs) were estimated with 95% confidence intervals (CI). RDW was evaluated separately as continuous and discrete (High RDW ≥ 14.5) variables. RESULTS: Four thousand one hundred and sixty-eight patients were included in this study, where 824 patients (19.8%) had a high RDW value ≥14.5% (High RDW: 64.7% were female, mean age 58 years [±22] vs. Normal RDW: 60.2% female, mean age 46 years [±19]). Eight hundred and twenty-nine patients had a hospitalization, where the median time between positive PCR and hospital entry was 5 [IQR 1-18] days. Models were analyzed with RDW (continuous) and adjusted for age, sex, comorbidities, and BMI suggested an OR of 1.242 [95% CI = 1.187-2.688] for hospitalization and an OR of 2.911 [95% CI = 1.928-4.395] for mortality (p < .001). RDW (discrete) with the same adjustments presented an OR of 2.232 [95% CI = 1.853-1.300] for hospitalization and an OR of 1.263 [95% CI = 1.166-1.368] for mortality (p < .001). CONCLUSIONS: High RDW values obtained from community blood tests are associated with greater odds of hospitalization and mortality for patients with COVID-19.KEY MESSAGESRDW measures before SARS-CoV-2 infection is a predictive factor for hospitalization and mortality.RDW threshold of 14.5% provides high sensitivity and specificity for COVID-19 related mortality, comparatively to other blood tests.Patient records should be accessed by clinicians for prior RDW results, if available, followed by further monitoring.