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Tag: antibodies
June 7, 2021
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…
June 1, 2021
Correlation of Vaccine-Elicited Antibody Levels and Neutralizing Activities against SARS-CoV-2 and Its Variants
[Pre-print, not peer-reviewed] Analysis of sera from individuals fully vaccinated with the Pfizer-BioNTech (n=30) and Moderna (n=19) vaccines ≥22 days after the second dose showed that neutralizing activity against pseudoviruses bearing mutated spike proteins from variants of concern was detectable in all participants but was reduced by 7-10 fold against the B.1.351 variant. Anti-SARS-CoV-2 IgG…
A Population-Based Analysis of the Longevity of SARS-CoV-2 Antibody Seropositivity in the United States
An observational study of 39,086 US individuals with PCR-confirmed COVID-19 followed up to 10 months from March 2020 to January 2021 found that prevalence of anti-SARS-CoV-2 IgG spike (S) and nucleocapsid (N) antibodies reached approximately 90% 21 days after infection, then declined to 88% for S antibodies and 68% for N antibodies after 10 months….
May 26, 2021
Monoclonal Antibody Treatment Prophylaxis and Vaccines Combined to Reduce SARS CoV-2 Spread
[Pre-print, not peer-reviewed] A modeling study of SARS-CoV-2 transmission in the US population found that allocating monoclonal antibodies (mAbs) as post-exposure prophylaxis (PEP) and treatment of persons with COVID-19 in combination with a vaccination program could substantially reduce infections and mortality. Allocation of mAbs as PEP to persons >65 years of age averted up to…
Single-Dose SARS-CoV-2 Vaccine in a Prospective Cohort of COVID-19 Patients
[Pre-print, not peer-reviewed] A study comparing antibody responses in 155 previously SARS-CoV-2 infected individuals found a single dose of the Pfizer-BioNTech vaccine provided neutralizing antibody titers exceeding those produced following two vaccine doses in 49 previously uninfected healthcare workers. Additionally, pre-vaccination neutralization titers in persons with previous infection were associated with higher neutralization titers after…
Influence of Past Infection with SARS-CoV-2 on the Response to the BioTech Pfizer BNT162b2 MRNA Vaccine in Health Care Workers Kinetics and Durability of the Humoral Response
[Pre-print, not peer-reviewed] A cohort study of 63 hospital healthcare workers in Spain who received 2 doses of the Pfizer-BioNTech vaccine found that those with a previous SARS-CoV-2 infection developed a 126-fold increase in antibody levels after 1 dose and maintained higher antibody levels than SARS-CoV-2 naïve workers after the 2nd dose. Healthcare workers with…
SARS-CoV-2 Antibody Testing in Healthcare Workers a Comparison of the Clinical Performance of Three Commercially Available Antibody Assays
[Pre-print, not peer-reviewed] A comparison of commercially available SARS-CoV-2 antibody assays found that the Roche Anti-SARS-CoV-2 anti-nucleocapsid Total Antibody test (Roche) detected antibodies for at least seven months after confirmed natural infection with while sensitivity of the Abbott Anti-SARS-CoV-2 anti-nucleocapsid IgG (Abbott) declined over time. Among serum samples from healthcare workers (N=5,788) with previously confirmed…
May 18, 2021
Individuals Who Were Mildly Symptomatic Following Infection with SARS-CoV-2 B.1.1.28 Have Neutralizing Antibodies to the P.1 Variant
[Pre-print, not peer-reviewed] 84% of sera from to individuals (n=60) recovered from mild SARS-CoV-2 infection caused by the B.1.1.28 variant (the wild-type strain circulating in Brazil) had neutralizing antibodies against the P.1 variant of concern. Neutralization titers against the wild-type strain were consistently higher compared to the P.1 variant, but the differences were not more…
May 11, 2021
Prevalence of Antibody Positivity to SARS-CoV-2 Following the First Peak of Infection in England: Serial Cross-Sectional Studies of 365,000 Adults
The prevalence of anti-spike SARS-CoV-2 antibodies in England was 5% by the end of September 2020 (prior to the onset of vaccination campaigns), according to three cross-sectional national surveys with non-overlapping random samples undertaken between late June to September (n>365,000). The prevalence of detectable antibodies over the three rounds was 6%, 5%, and 4%. The…
Asymptomatic Individuals Positive for Anti-SARS-CoV-2 Antibodies Negative on Molecular Swab
Only 1% (n=212) of over 16,000 frontline workers developed detectable anti-SARS-CoV-2 antibodies during screening in Italy from May to June 2020. Among antibody-positive individuals, only one tested positive for SARS-CoV-2 RNA under a protocol that required antibody-positive participants to be given a PCR test. The authors suggest that performing a PCR test on antibody-positive participants…
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