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Tag: antibodies
March 5, 2021
Time Series Analysis and Mechanistic Modelling of Heterogeneity and Sero-Reversion in Antibody Responses to Mild SARS-CoV-2 Infection
A prospective serology cohort study among UK healthcare workers found that by 21 weeks, 22% (31 of 143) of those previously positive for anti-SARS-CoV-2 spike (S1) antibodies reverted to being S1 negative, while only 4% (6 of 150) of those previously positive for anti-SARS-CoV-2 nucleocapsid (NP) antibodies reverted to being NP negative, which the authors…
Resistance of SARS-CoV-2 Variants to Neutralization by Monoclonal and Serum-Derived Polyclonal Antibodies
Most convalescent sera from people who had recovered from mild COVID-19 (n=29) and virtually all Pfizer-BioNTech mRNA vaccine-induced immune sera (n=24) were shown to have diminished neutralizing activity against engineered SARS-CoV-2 strains including a chimeric strain combining a strain identified in Washington state with a B.1.351 spike gene (Wash SA-B.1.351 strain), or recombinant viruses containing…
March 3, 2021
SARS-CoV-2 Antibodies Detected in Human Breast Milk Post-Vaccination
[Pre-print, not peer-reviewed] Significantly elevated levels of SARS-CoV-2 specific IgG and IgA antibodies were observed in breast milk starting 7 days after the initial vaccine dose in a cohort study of six lactating women who had received both doses of either the Pfizer/BioNTech or Moderna vaccines. The authors note that the response following vaccination was…
March 2, 2021
REACT-2 Round 5 Increasing Prevalence of SARS-CoV-2 Antibodies Demonstrate Impact of the Second Wave and of Vaccine Roll-out in England
[Pre-print, not peer-reviewed] A nationwide cross-sectional study in the England (n=172,000) conducted between January 26 to February 8, 2021 found that the SARS-CoV-2-specific antibody seroprevalence representative of the national population was 14% overall. This figure included seroprevalence due to both immunization and infection. Seroprevalence in unvaccinated people was highest in London and among members of…
Binding and Neutralization Antibody Titers After a Single Vaccine Dose in Health Care Workers Previously Infected With SARS-CoV-2
A single dose of mRNA vaccine (Pfizer or Moderna vaccine) elicited higher antibody and neutralization titers in health care workers (n=59) with previous serology-confirmed SARS-CoV-2 infection compared to healthcare workers who were seronegative at baseline. At 14 days post-vaccination, antibody binding strength to SARS-CoV-2 antigens from participants with both asymptomatic and symptomatic prior infection were…
Reduced Antibody Cross-Reactivity Following Infection with B.1.1.7 than with Parental SARS-CoV-2 Strains
[Pre-print, not peer-reviewed] Convalescent sera from patients infected with the SARS-CoV-2 B.1.1.7 variant demonstrated reduced activity against reference strains from earlier in the pandemic. Neutralizing activity of sera isolated from patients that had confirmed infection by the SARS-CoV-2 B.1.1.7 variant (n=29) was reduced against a parental reference strain isolated from Wuhan by 3.4-fold. In contrast,…
February 26, 2021
Seasonal Human Coronavirus Antibodies Are Boosted upon SARS-CoV-2 Infection but Not Associated with Protection
Cross reactive antibodies generated by pre-pandemic human coronavirus (hCoV) infections are common but are not associated with protection against infection or poor clinical outcomes after infection with SARS-CoV-2. Using samples from a pre-pandemic biobank, 4% of pre-pandemic sera contained antibodies that bound the full-length spike from SARS-CoV-2 and 16% of samples contained antibodies capable of…
Bamlanivimab Does Not Neutralize Two SARS-CoV-2 Variants Carrying E484K in Vitro
[Pre-print, not peer-reviewed] An in vitro study of the neutralizing ability of the monoclonal antibody treatment bamlanivimab against five emerging SARS-CoV-2 variants of concern determined no neutralization effect could be detected against either the B.1.351 (first described in South Africa) or P.2 (first described in Brazil) variants, both of which harbor the E484K substitution. The…
February 22, 2021
Decreased Neutralization of SARS-CoV-2 Global Variants by Therapeutic Anti-Spike Protein Monoclonal Antibodies
[Pre-print, not peer-reviewed] A study testing the ability of therapeutic monoclonal antibodies REGN10933 and REGN10987 to neutralize SARS-CoV-2 variants B.1.1.7, B.1.351, mink cluster 5, and COH.20G/677H found that REGN10987 maintained most neutralization activity against viruses with B.1.1.7, B.1.351 and mink cluster 5 spike proteins. REGN10933 was not effective against B.1.351, which may be due to…
February 2, 2021
Rapid Expert Consultation on Allocating COVID-19 Monoclonal Antibody Therapies and Other Novel Therapeutics (January 29, 2021)
Around 75% of the 641,000 COVID-19 monoclonal antibody (mAb) therapies allocated by the Department of Health and Human Services to states and local territories were not administered in the period before January 6, 2021. As a response, a rapid consultation by the National Academies of Sciences, Engineering, and Medicine identified potential barriers, including the limited…
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