Performance evaluation of the Abbott Alinity Hepatitis C antigen next assay in a US urban emergency department population.

Introduction: HCV antibody assays have been used to screen for HCV, but confirmation of acute infection is dependent on RNA or core antigen testing. The aim of the study was to compare the performance of five HCV test methods, including RNA testing, on a US emergency department population.

Methods: Clinical performance metrics were calculated on 708 consenting Johns Hopkins Emergency Department patients who self-reported an increased risk for HCV infection.

Risk of Severe Acute Respiratory Syndrome Coronavirus 2 Infection Following Prior Infection or Vaccination.

Background: The extent to which infection versus vaccination has conferred similarly durable severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) immunity during the Omicron era remains unclear.

Methods: In a cohort of 4496 adults under continued serological surveillance throughout the first year of Omicron-predominant SARS-CoV-2 transmission, we examined incidence of new infection among individuals whose last known antigenic exposure was either recent (<90 days) or remote (≥90 days) infection or vaccination.

Results: We adjudicated 2053 new-onset infections occurring between 15 December 2021 through 22 December 2022.

Assessing the post hoc effectiveness of tixagevimab-cilgavimab for prevention of SARS-CoV-2 infections in solid organ transplant recipients.

Background: Tixagevimab-cilgavimab (Tix-Cil) was authorized for prophylaxis against COVID-19 in immunocompromised patients from December 2021 through January 2023. Real-world effectiveness for solid organ transplant (SOT) recipients has been unclear.

Methods: We enrolled 911 SOT recipients into a longitudinal COVID-19 serology study, of whom 381 (42%) received ≥1 dose of Tix-Cil.

Reduced Serological Response to COVID-19 Booster Vaccine is Associated with Reduced B Cell Memory in Patients With Inflammatory Bowel Disease; VARIATION [VAriability in Response in IBD AgainsT SARS-COV-2 ImmunisatiON].

Background And Aims: Patients with inflammatory bowel disease [IBD] have an attenuated response to initial COVID-19 vaccination. We sought to characterize the impact of IBD and its treatment on responses after the third vaccine against SARS-CoV-2.

Methods: This was a prospective multicentre observational study of patients with IBD [n = 202] and healthy controls [HC, n = 92].

Serological response to vaccination in post-acute sequelae of COVID.

Background: Individuals with post-acute sequelae of COVID (PASC) may have a persistence in immune activation that differentiates them from individuals who have recovered from COVID without clinical sequelae. To investigate how humoral immune activation may vary in this regard, we compared patterns of vaccine-provoked serological response in patients with PASC compared to individuals recovered from prior COVID without PASC.

Methods: We prospectively studied 245 adults clinically diagnosed with PASC and 86 adults successfully recovered from prior COVID.

SARS-CoV-2 Anti-Spike IgG Antibody and ACE2 Receptor Binding Inhibition Levels among Breakthrough Stage Veteran Patients.

SARS-CoV-2 mRNA vaccines have been critical to curbing pandemic COVID-19; however, a major shortcoming has been the inability to assess levels of protection after vaccination. This study assessed serologic status of breakthrough infections in vaccinated patients at a Veterans Administration medical center from June through December 2021 during a SARS-CoV-2 delta variant wave. Breakthrough occurred mostly beyond 150 days after two-dose vaccination with a mean of 239 days.

Awareness of SARS-CoV-2 Omicron Variant Infection Among Adults With Recent COVID-19 Seropositivity.

Importance: Some individuals who were infected by the SARS-CoV-2 Omicron variant may have been completely unaware of their infectious status while the virus was actively transmissible.

Objective: To examine awareness of infectious status among individuals during the recent Omicron variant surge in a diverse and populous urban region of Los Angeles County.

Design, Setting, And Participants: This cohort study analyzed the records of adult employees and patients of an academic medical center who were enrolled in a longitudinal COVID-19 serological study in Los Angeles County, California.

Specificity and Confirmation of SARS-CoV-2 Serological Test Methods in Emergency Department Populations across the United States.

Background: Serological testing for SARS-CoV-2 is integral for understanding prevalence of disease, tracking of infections, confirming humoral response to vaccines, and determining timing and efficacy of boosters. The study objective was to compare the specificity of serology assays in emergency department populations across the United States in 2019 (pre-pandemic) and early 2020, incorporating an automated confirmatory assay.

Methods: Patient specimens (n = 1954) were from 4 regions in the United States: New York, NY; Milwaukee, WI; Miami, FL; and Los Angeles, CA.

Specificity and Confirmation of SARS-CoV-2 Serological Test Methods in Emergency Department Populations Across the United States in 2019 and Early 2020.

Background: Serological testing for SARS-CoV-2 is integral for understanding prevalence of disease, tracking of infections, confirming humoral response to vaccines, and determining timing and efficacy of boosters. The study objective was to compare the specificity of serology assays in emergency department populations across the United States in 2019 (pre-pandemic) early 2020 incorporating an automated confirmatory assay.

Methods: Patient specimens (n = 1954) were from four regions in the United States: New York, NY; Milwaukee, WI; Miami, FL; and Los Angeles, CA.

Demographic and clinical characteristics associated with variations in antibody response to BNT162b2 COVID-19 vaccination among healthcare workers at an academic medical centre: a longitudinal cohort analysis.

Objectives: We sought to understand the demographic and clinical factors associated with variations in longitudinal antibody response following completion of two-dose regiment of BNT162b2 vaccination.

Design: This study is a 10-month longitudinal cohort study of healthcare workers and serially measured anti-spike protein IgG (IgG-S) antibody levels using mixed linear models to examine their associations with participant characteristics.

Setting: A large, multisite academic medical centre in Southern California, USA.

Predominance of antibody-resistant SARS-CoV-2 variants in vaccine breakthrough cases from the San Francisco Bay Area, California.

Associations between vaccine breakthrough cases and infection by different SARS coronavirus 2 (SARS-CoV-2) variants have remained largely unexplored. Here we analysed SARS-CoV-2 whole-genome sequences and viral loads from 1,373 persons with COVID-19 from the San Francisco Bay Area from 1 February to 30 June 2021, of which 125 (9.1%) were vaccine breakthrough infections.

The T-cell clonal response to SARS-CoV-2 vaccination in inflammatory bowel disease patients is augmented by anti-TNF therapy and often deficient in antibody-responders.

Background: Vaccination against SARS-CoV-2 is a highly effective strategy to protect against infection, which is predominantly mediated by vaccine-induced antibodies. Postvaccination antibodies are robustly produced by those with inflammatory bowel disease (IBD) even on immune-modifying therapies but are blunted by anti-TNF therapy. In contrast, T-cell response which primarily determines long-term efficacy against disease progression,, is less well understood.

Longitudinal SARS-CoV-2 mRNA Vaccine-Induced Humoral Immune Responses in Patients with Cancer.

Longitudinal studies of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccine-induced immune responses in patients with cancer are needed to optimize clinical care. In a prospective cohort study of 366 (291 vaccinated) patients, we measured antibody levels [anti-spike (IgG-(S-RBD) and anti-nucleocapsid immunoglobulin] at three time points. Antibody level trajectories and frequency of breakthrough infections were evaluated by tumor type and timing of treatment relative to vaccination.

Antibody responses to the BNT162b2 mRNA vaccine in individuals previously infected with SARS-CoV-2.

In a cohort of BNT162b2 (Pfizer-BioNTech) mRNA vaccine recipients (n = 1,090), we observed that spike-specific IgG antibody levels and ACE2 antibody binding inhibition responses elicited by a single vaccine dose in individuals with prior SARS-CoV-2 infection (n = 35) were similar to those seen after two doses of vaccine in individuals without prior infection (n = 228). Post-vaccine symptoms were more prominent for those with prior infection after the first dose, but symptomology was similar between groups after the second dose.

Engineering of the hepatitis C virus helicase for enhanced seroreactivity.

Hepatitis C Virus c33, a recombinant protein comprising residues 1192-1457 of NS3 helicase, has been a mainstay of HCV serology for decades. With seven unpaired cysteines, seroreactivity of E. coli expressed c33 is dependant on reductants.

Evaluation of the Abbott ARCHITECT Toxo IgM assay.

Development of the ARCHITECT Toxo IgM assay has been done to assist the clinician in acute Toxoplasma gondii infection detection, especially in pregnant women. Its use, in conjunction with ARCHITECT Toxo IgG and Toxo Avidity assays, will provide an array of assays particularly useful in the monitoring of pregnant females to determine the risk of maternal transmission of the parasite. Specificity results from 2 testing sites, using populations of pregnant females, hospital patients, and blood donors, demonstrated that the assay has an overall resolved relative specificity of 99.