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* Variants may cause few breakthrough infections in
vaccinated
* Researchers find no evidence of widespread virus escape
* Past infection with B117/Alpha confers broad protection
(Recasts, adds details on Pfizer-BioNTech vaccine)
By Ludwig Burger and Aishwarya Nair
June 22 (Reuters) - COVID-19 vaccines made by AstraZeneca
and the Pfizer-BioNTech alliance
remain broadly effective against Delta and Kappa variants of the
COVID-19 causing virus, which were first identified in India,
according to a scientific study, underpinning a continued push
to deliver the shots.
The study by Oxford University researchers, published in the
journal Cell, investigated the ability of antibodies in the
blood from people, who were vaccinated with the two-shot
regimens, to neutralize the highly contagious Delta and Kappa
variants, a statement said.
"There is no evidence of widespread escape suggesting that
the current generation of vaccines will provide protection
against the B.1.617 lineage," the paper said, referring to the
Delta and Kappa variants by a commonly used code.
However, the concentration of neutralising antibodies in the
blood was somewhat reduced, which may lead to some breakthrough
infections, they cautioned.
Last week, an analysis by the Public Health England (PHE)
showed that vaccines made by Pfizer Inc and AstraZeneca
offer high protection of more than 90% against hospitalization
from the Delta variant.
"We are encouraged to see the non-clinical results published
from Oxford and these data, alongside the recent early
real-world analysis from Public Health England, provide us with
a positive indication that our vaccine can have significant
impact against the Delta variant," AstraZeneca executive Mene
Pangalos said in a separate statement.
The Delta variant is becoming the globally dominant version
of the disease, the World Health Organization's chief scientist
said on Friday.
The Oxford researchers also analysed reinfection patterns in
people who had previously had COVID-19. The risk of reinfection
with the Delta variant appeared particularly high in individuals
previously infected by the Beta and Gamma lineages that emerged
in South Africa and Brazil, respectively.
By contrast, previous infection with the Alpha, or B117,
variant first detected in Britain, conferred "reasonable"
cross-protection against all variants of concern, lending itself
as a template that next-generation vaccines could be molded on.
"B117 might be a candidate for new variant vaccines to
provide the broadest protection," the researchers said.
(Reporting by Aishwarya Nair in Bengaluru; Editing by Arun
Koyyur and David Evans)
