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LONDON, Dec 10 (Reuters) - Booster COVID-19 vaccine shots
give an estimated 70% to 75% protection against mild disease
from the new Omicron variant, the UK Health Security Agency said
on Friday, citing initial findings from a real-world study.
The findings are some of the earliest data on the protection
against Omicron outside of lab studies, which have shown reduced
neutralising activity against Omicron.
The early real-world data suggest that while Omicron could
greatly reduce the protection against mild disease from an
initial two-dose vaccination course, boosters restored the
protection to an extent.
"These early estimates should be treated with caution but
they indicate that a few months after the second jab, there is a
greater risk of catching the Omicron variant compared to Delta
strain," said Dr Mary Ramsay, Head of Immunisation at the UKHSA,
adding that protection against severe disease was expected to
remain higher.
"The data suggest this risk is significantly reduced
following a booster vaccine, so I urge everyone to take up their
booster when eligible."
In an analysis of 581 people with confirmed Omicron, two
doses of AstraZeneca and Pfizer-BioNTech
vaccines provided much lower levels of protection
against symptomatic infection compared to what they provide
against Delta.
However, when boosted with a dose of Pfizer vaccine, there
was around 70% protection against symptomatic infection for
people who initially received AstraZeneca, and around 75%
protection for those who received Pfizer.
That compares to estimated protection against infection from
Delta following a booster of around 90%.
UKHSA said that, at current trends, Omicron would account
for more that 50% of all COVID-19 infections by mid-December,
with Britain exceeding one million infections by the end of the
month.
(Reporting by Alistair Smout; editing by James Davey)
