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“Neutralization of N501Y mutant SARS-CoV-2 by BNT162b2 vaccine-elicited sera” was published as a preprint yesterday. The N501Y substitution is present in both the South African and UK (B117) variant.https://www.biorxiv.org/content/10.1101/2021.01.07.425740v1.full.pdf
Recently, data was shared showing that previous infection with SARS-CoV-2 induces antibody responses capable of neutralising a variant harbouring N501Y substitution.
The important question was, will serum post-vaccination do the same as post-infection? https://twitter.com/andrew_croxford/status/1341463380415160320?s=20
The important question was, will serum post-vaccination do the same as post-infection? https://twitter.com/andrew_croxford/status/1341463380415160320?s=20
The assay works by mixing serum with viral particles, you incubate them for a while to allow antibody binding, then serially dilute the mixture onto a host cell monolayer. After a few days count the ‘plaques’, which are discernible regions of infected cells.
Key result: "The ratio of the 50% neutralization GMT of the sera against the Y501 virus to that against the N501 virus was 1.46, indicating NO REDUCTION IN NEUTRALIZING ACTIVITY against the virus bearing the Y501 spike."
Serum samples were taken from patients who received *two* doses (30μg) of BNT162b2, three weeks apart (the recommended dose regimen from the trial). Sera was isolated from people either 2 or 4 weeks after the second dose (indicated in this figure by circles or triangles).
We are still not sure how serum would perform in this assay before the boost on d21. It is possible based on the preliminary data that neutralisation of SARS-CoV-2 would be less effective after a single dose. Still waiting for the immunogenicity data from later trials.
“A limitation of this finding is that the Y501 virus does not include the full set of spike mutations found on the rapidly spreading strains in the UK or South Africa.”
We must perform the same experiment B117 with the serum post-Pfizer or AstraZeneca vaccine with some urgency.
We must perform the same experiment B117 with the serum post-Pfizer or AstraZeneca vaccine with some urgency.
This experiment is planned and will be our moment of collective ‘exhale’. Very much looking forward to that, and it has been on the PHE agenda since those ‘NERVTAG’ minutes. They are working on it, for sure! https://twitter.com/andrew_croxford/status/1340686607691689984?s=20
And Ugur Sahin is confident it will work. That's actually enough for me. https://twitter.com/andrew_croxford/status/1341447968679981059?s=20
