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Tag: immunity
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…
SARS-CoV -2 Antibody Persistence in COVID-19 Convalescent Plasma Donors: Dependency on Assay Format and Applicability to Serosurveillance
SARS-CoV-2 antibody responses were shown to increase over time in a study of plasma collected up to 63-129 days following symptom resolution from 18 patients recovered from COVID-19 when using direct double Ag-sandwich assays (Ortho Total Ig and Roche Total Ig). By contrast, measurements from indirect binding assays showed a declining antibody response. Due to…
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[Pre-print, not peer-reviewed] The presence of SARS-CoV-2 anti-nucleocapsid antibodies at baseline was associated with almost 80% protection against SARS-CoV-2 re-infection for a period of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…
June 10, 2021
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[Pre-print, not peer-reviewed] AX290 and AX677 (AXON Neuroscience), second generation monoclonal antibodies developed specifically to target SARS-CoV-2 variants of concern, were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…
Immunogenicity of Ad26.COV2.S Vaccine against SARS-CoV-2 Variants in Humans
Median anti-SARS-CoV-2 neutralizing antibody titers of sera from individuals vaccinated with the Johnson & Johnson-Janssen vaccine in the phase 1/2 trials (n=20) were 5- and 3-fold lower against the B.1.351 (Beta) and P.1 (Gamma) variants, respectively, compared with the wild-type strain on day 71 following vaccination. Binding antibody titers were impaired but to a lesser…
June 9, 2021
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
Neutralising Antibody Activity against SARS-CoV-2 VOCs B.1.617.2 and B.1.351 by BNT162b2 Vaccination
A study of the effectiveness of neutralizing antibody titers (NAbTs) against the B.1.617.2 SARS-CoV-2 variant, first identified in India and now widely circulating in the UK, found that two doses of the Pfizer-BioNTech vaccine elicited anti-wild-type spike antibodies in all participants, while NAbTs were reduced 5.8-fold against B.1.617.2 relative to wild-type, a significantly greater reduction…
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…
Naturally Acquired SARS-CoV-2 Immunity Persists for up to 11 Months Following Infection
A longitudinal study of convalescent plasma donors (n = 228) detected anti-SARS-CoV-2 antibodies in 97% of donors at initial presentation, and found that 91.4% of the 116 donors presenting for repeat timepoints had detectable IgG levels up to 11 months post-symptom recovery. The VITROS® Anti-SARS-CoV-2 Total and IgG assays, and an in-house fluorescence reduction neutralization…
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