A retrospective analysis of clinical features of patients hospitalized with SARS-CoV-2 Omicron variants BA.1 and BA.2.

The causative agent of the ongoing Corona virus disease 2019 (COVID-19) pandemic, Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has acquired a considerable amount of mutations, leading to changes in clinical manifestations and increased transmission. Recent studies based on animal disease models and data from the general population were reporting a higher pathogenicity of the BA.2 sublineage compared to BA.1. The aim of this study was to provide real world data on patients with the SARS-CoV-2 Omicron BA.1 and BA.2 subvariants treated at our center, highlighting similarities and differences in the clinical disease course. We retrospectively collected and analyzed the data of adult patients admitted with confirmed SARS-CoV-2 infection at the Department for Infectious Diseases and Tropical Medicine, Klinik Favoriten, Vienna, Austria. Patient characteristics including age, underlying diseases, vaccination status and outcome were compared between patients with the BA.1 and BA.2 subvariants. Between January 2022 and May 2022 we included 168 patients infected with Omicron BA.1 and 100 patients with BA.2. Patients admitted with BA.2 were significantly older, more often fully immunized and required less dexamethasone than patients with BA.1. No substantial differences were identified between patients infected with BA.1 and BA.2 regarding BMI, laboratory findings, need for supplemental oxygen, mortality and other evaluated comorbidities excepting active malignancies. The significantly larger percentage of fully immunized patients admitted with BA.2 is pointing to an increased transmissibility of this subvariant, while the comparable outcome of a somewhat older and sicker patient population might be indicative of reduced virulence.

Evaluation of Five Commercial SARS-CoV-2 Antigen Tests in a Clinical Setting.

BACKGROUND: Point-of-care antigen tests (AgTs) for the detection of severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) enable the rapid testing of infected individuals and are easy-to-use. However, there are few studies evaluating their clinical use. OBJECTIVE: The present study aimed to evaluate and compare the clinical performance characteristics of various commercial SARS-CoV-2 AgTs. DESIGN: The sensitivity of five AgTs, comprising four rapid antigen tests (RAT; AMP Rapid Test SARS-CoV-2 Ag, NADAL COVID-19 Antigen Rapid Test, CLINITEST Rapid COVID-19 Antigen Test, and Roche SARS-CoV-2 Rapid Antigen Test) and one sandwich chemiluminescence immunoassay (CLIA; LIAISON SARS-CoV-2 Assay), were evaluated in 300 nasopharyngeal (NP) swabs. Reverse transcriptase (RT) polymerase chain reaction (PCR) was used as a reference method. PARTICIPANTS: NP swabs were collected from patients admitted to hospital due to COVID-19. KEY RESULTS: Sensitivities of the AgTs ranged from 64.9 to 91.7% for samples with RT-PCR cycle threshold (Ct) values lower than 30 and were 100% for cycle threshold (Ct) values lower than 20. The highest sensitivity was observed for CLINITEST Rapid COVID-19 Antigen Test, and Roche SARS-CoV-2 rapid antigen test. Multivariate analysis using time from symptom onset and the Ct value for AgT sensitivity showed an inverse correlation. Further, the female sex was an independent factor of lower RAT sensitivity. CONCLUSIONS: Antigen tests from NP swab samples show high sensitivity in patients with a Ct value < 20. The best clinical sensitivity can be obtained using AgTs within the first 6 days after symptom onset.

COVID-19 serology in nephrology healthcare workers.

BACKGROUND: Chronic kidney disease patients show a high mortality in cases of a severe acute respiratory syndrome coronavirus-2 (SARS-CoV­2) infection. Thus, information on the sero-status of nephrology personnel might be crucial for patient protection; however, limited information exists about the presence of SARS-CoV­2 antibodies in asymptomatic individuals. METHODS: We examined the seroprevalence of SARS-CoV­2 IgG and IgM antibodies among healthcare workers of a tertiary care kidney center during the the first peak phase of the corona virus disease 2019 (COVID-19) crisis in Austria using an orthogonal test strategy and a total of 12 commercial nucleocapsid protein or spike glycoprotein-based assays as well as Western blotting and a neutralization assay. RESULTS: At baseline 60 of 235 study participants (25.5%, 95% confidence interval, CI 20.4-31.5%) were judged to be borderline positive or positive for IgM or IgG using a high sensitivity/low specificity threshold in one test system. Follow-up analysis after about 2 weeks revealed IgG positivity in 12 (5.1%, 95% CI: 2.9-8.8%) and IgM positivity in 6 (2.6%, 95% CI: 1.1-5.6) in at least one assay. Of the healthcare workers 2.1% (95% CI: 0.8-5.0%) showed IgG nucleocapsid antibodies in at least 2 assays. By contrast, positive controls with proven COVID-19 showed antibody positivity among almost all test systems. Moreover, serum samples obtained from healthcare workers did not show SARS-CoV­2 neutralizing capacity, in contrast to positive controls. CONCLUSION: Using a broad spectrum of antibody tests the present study revealed inconsistent results for SARS-CoV­2 seroprevalence among asymptomatic individuals, while this was not the case among COVID-19 patients. TRIAL REGISTRATION NUMBER: CONEC, ClinicalTrials.gov number NCT04347694.