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Tag: antibodies
June 15, 2021
Young Infants Exhibit Robust Functional Antibody Responses and Restrained IFN-γ Production to SARS-CoV-2
A study evaluating the immune responses in four infants with mild COVID-19 (median age 7 weeks old) found that compared to their parents who also had COVID-19 (n=8) and a cohort of adult controls with prior COVID-19 (n=10), infants had higher anti-SARS-CoV-2 IgG antibody levels in both sera and saliva and exhibited more robust serum…
June 14, 2021
Impact of Baseline SARS-CoV-2 Antibody Status on Syndromic Surveillance and the Risk of Subsequent Covid-19 – a Prospective Multicentre Cohort Study
[Pre-print, not peer-reviewed] The presence of SARS-CoV-2 anti-nucleocapsid antibodies at baseline was associated with almost 80% protection against SARS-CoV-2 re-infection for a period of at least eight months, according to a study of healthcare workers (HCW) in Switzerland. Among 4,818 participants, 144 (3%) were seropositive at baseline. Among 2,713 participants with ≥1 SARS-CoV-2 test during…
A Comparison of SARS-CoV-2 Nucleocapsid and Spike Antibody Detection Using Three Commercially Available Automated Immunoassays
A study comparing the Abbott SARS-CoV-2 nucleocapsid IgG, Beckman-Coulter SARS-CoV-2 spike IgG, and Roche Anti-SARS-CoV-2 nucleocapsid total antibody assays found that all three demonstrated 100% specificity, and sensitivities of 98%, 93%, and 90%, respectively. After the exclusion of samples from immunocompromised patients, all assays exhibited ≥95% sensitivity. In sequential samples collected from the same individuals,…
June 10, 2021
Highly-Specific Memory B Cells Generation after the 2nd Dose of BNT162b2 Vaccine Compensate for the Decline of Serum Antibodies and Absence of Mucosal IgA
[Pre-print, not peer-reviewed] The Pfizer-BioNTech vaccine only elicited a short-lived mucosal IgA antibody response in a study of 108 vaccinated healthcare workers (HCWs) in Italy without prior infection, with none of the vaccinated HCWs tested for mucosal IgA having a detectable response 2-3 weeks after the second dose. By contrast, the vaccine elicited robust memory…
Second Generation Antibodies Neutralize Emerging SARS-CoV-2 Variants of Concern
[Pre-print, not peer-reviewed] AX290 and AX677 (AXON Neuroscience), second generation monoclonal antibodies developed specifically to target SARS-CoV-2 variants of concern, were experimentally shown to successfully neutralize the wild-type strain, B.1.1.7 (Alpha), and B.1.351 (Beta) in mouse models. Kovacech et al. (June 9, 2021). Second Generation Antibodies Neutralize Emerging SARS-CoV-2 Variants of Concern. Pre-print downloaded Jun 10…
Antibodies Elicited by mRNA-1273 Vaccination Bind More Broadly to the Receptor Binding Domain than Do Those from SARS-CoV-2 Infection
Vaccine-elicited anti-SARS-CoV-2 antibodies in individuals fully vaccinated with the Moderna vaccine in phase 1/2 trials (n=14) were found to target more epitopes within the receptor binding domain (RBD) when compared to individuals with prior infection. Binding of vaccine-elicited antibodies was more broadly distributed across epitopes compared to infection-elicited antibodies within the RBD, which the authors…
June 9, 2021
Delayed Antibody and T-Cell Response to BNT162b2 Vaccination in the Elderly, Germany
In a cohort of elderly residents of an assisted living facility in Germany (n=71, median age 81 years) vaccinated with the Pfizer-BioNTech vaccine only 46% (24 of 52) developed neutralizing antibodies 3 weeks after the first dose and 90% (63 of 70) 4 weeks after the second dose. In contrast, 91% (97 of 107) of…
Seroprevalence of SARS-CoV-2 Antibodies Among Rural Healthcare Workers
[Pre-print, not peer-reviewed] In rural healthcare centers in South Dakota, a seroprevalence study revealed that prevalence of anti-SARS-CoV-2 antibodies in healthcare workers at each clinical site was higher than the reported cumulative incidence of COVID-19 in the general population of each respective county. The prevalence of anti-SARS-CoV-2 antibodies among healthcare workers employed at clinics in…
Functional Characterization of SARS-CoV-2 Vaccine Elicited Antibodies in Immunologically Nave and Pre-Immune Humans
[Pre-print, not peer-reviewed] The Pfizer-BioNTech vaccine elicited higher neutralizing and anti-SARS-CoV-2 antibody binding responses in individuals with prior infection (n=32) compared to those without prior infection (n=20). The second vaccine dose did not significantly increase neutralizing or binding antibody levels in individuals with prior infection, whereas the second dose was required to induce antibody responses…
June 7, 2021
Marked Increase in Avidity of Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) Antibodies 7-8 Months after Infection Is Not Diminished in Old Age
A study assessing the avidity, or binding strength, of IgG among 217 participants in Austria soon after SARS-CoV-2 infection and 7-8 months later found that avidity increased from 18% to 42% and did not diminish among older participants. High avidity was associated with a residual neutralization capacity in 97% of participants (211/217). The authors suggest…
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