Researchers discover antibodies that neutralize omicron and other SARS-CoV-2 variants

“The recently emerged SARS-CoV-2 Omicron variant encodes 37 amino acid substitutions in the spike (S) protein, 15 of which are in the receptor-binding domain (RBD), thereby raising concerns about the effectiveness of available vaccines and antibody therapeutics…. The magnitude of Omicron-mediated immune evasion marks a major SARS-CoV-2 antigenic shift. Broadly neutralizing mAbs recognizing RBD epitopes conserved among SARS-CoV-2 variants and other sarbecoviruses may prove key to controlling the ongoing pandemic and future zoonotic spillovers.”

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Researchers discover antibodies that neutralize omicron and other SARS-CoV-2 variants

Protection and waning of natural and hybrid COVID-19 immunity

“Protection from reinfection decreases with time since previous infection, but is, nevertheless, higher than that conferred by vaccination with two doses at a similar time since the last immunity-conferring event. A single vaccine dose after infection helps to restore protection.”

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Protection and waning of natural and hybrid COVID-19 immunity

WHO international standard for SARS-CoV-2 antibodies to determine markers of protection

“One of the important elements of regulatory evaluation is the measurement of the vaccine-induced immune response, for which guidance is available in the WHO guidelines on the clinical evaluation of vaccines. Evaluation of the immunogenicity of a vaccine aims to identify a possible correlate of protection. Although it is still unclear what such a correlate could be for SARS-CoV-2, neutralising or binding antibodies are good candidates. However, identification of a correlate of protection requires the comparison of immunological data from different clinical trials, but is often confounded by the differences in assays, target antigens, numerical readouts, and endpoints.”

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WHO international standard for SARS-CoV-2 antibodies to determine markers of protection

Understanding neutralising antibodies against SARS-CoV-2 and their implications in clinical practice

“We summarise the onset and persistence of IgA, IgM and IgG antibodies, and we explore their roles in neutralising SARS-CoV-2, their persistence in convalescent individuals, and in reinfection. Furthermore, we also review the applications of neutralising antibodies in the clinical setting—from predictors of disease severity to serological testing to vaccinations, and finally in therapeutics such as convalescent plasma infusion.”

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Understanding neutralising antibodies against SARS-CoV-2 and their implications in clinical practice

Covid-19 Breakthrough Infections in Vaccinated Health Care Workers

“Among fully vaccinated health care workers, the occurrence of breakthrough infections with SARS-CoV-2 was correlated with neutralizing antibody titers during the peri-infection period. Most breakthrough infections were mild or asymptomatic, although persistent symptoms did occur.”

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Covid-19 Breakthrough Infections in Vaccinated Health Care Workers

Neutralizing antibody levels are highly predictive of immune protection from symptomatic SARS-CoV-2 infection

“Modeling of the decay of the neutralization titer over the first 250 d after immunization predicts that a significant loss in protection from SARS-CoV-2 infection will occur, although protection from severe disease should be largely retained. Neutralization titers against some SARS-CoV-2 variants of concern are reduced compared with the vaccine strain, and our model predicts the relationship between neutralization and efficacy against viral variants. Here, we show that neutralization level is highly predictive of immune protection, and provide an evidence-based model of SARS-CoV-2immune protection that will assist in developing vaccine strategies to control the future trajectory of the pandemic.”

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Neutralizing antibody levels are highly predictive of immune protection from symptomatic SARS-CoV-2 infection