Boosters significantly restore protection vs Omicron, UK says
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[December 11, 2021]
By Alistair Smout
LONDON (Reuters) -Booster COVID-19 shots significantly restore
protection against mild disease caused by the Omicron variant, in part
reversing an otherwise steep drop in vaccine effectiveness, the UK
Health Security Agency said on Friday.
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The early findings from a real-world analysis are some of the
earliest data on the protection against Omicron outside of lab
studies, which have shown reduced neutralising activity against
Omicron.
"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 or Pfizer-BioNTech vaccines provided much lower levels
of protection against symptomatic infection compared with what they
provide against Delta.
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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 with estimated protection against infection from Delta
following a booster of around 90%.
UKHSA reiterated it found that Omicron had a growth advantage over
Delta, and a 3-to-8 fold increased risk of reinfection.
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![](http://archives.lincolndailynews.com/2021/Dec/11/images/ads/current/rohlfs_lda_072017.png) It said two UK studies which
have yet to be presented publicly and three
international studies suggested Omicron gave a
20 to 40-fold reduction in neutralising
antibodies compared with the viruses used to
develop vaccines.
UKHSA said that while no cases of Omicron had
yet resulted in hospitalisation or death, the
was insufficient data to assess the severity of
Omicron.
At current growth rates, Omicron would account
for more that 50% of all COVID-19 infections by
mid-December, UKHSA said, with Britain exceeding
one million infections by the end of the month,
as new measures come into force in England to
slow the spread of Omicron.
"Rising cases of the Omicron variant coupled
with the new data today should be a wake-up call
for those who haven’t yet had their booster or,
indeed, any vaccine," National Health Service
medical director Stephen Powis said.
(Reporting by Alistair Smout; editing by James
Davey and Andrew Heavens)
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