(Adds detail, background)
LONDON, Nov 25 (Reuters) - A newly identified coronavirus
variant that has spread in South Africa is the most concerning
that British health officials have seen as it has double the
number of mutations of the Delta variant including some
associated with evading immune response.
The UK Health Security Agency said that the variant - called
B.1.1.529 - has a spike protein that was dramatically different
to the one in the original coronavirus that COVID-19 vaccines
are based on.
It has mutations that are likely to evade the immune
response generated both by prior infection and vaccination, and
also mutations associated with increased infectivity.
Lab studies are needed to assess the likelihood of the
mutations resulting in greatly reduced vaccine efficacy,
scientists said.
Earlier on Thursday, South African scientists said they had
detected the new COVID-19 variant in small numbers and were
working to understand its potential implications.
The variant has a "very unusual constellation" of mutations,
which are concerning because they could help it evade the body's
immune response and make it more transmissible, the scientists
told reporters at a news conference.
The variant has also been found in Botswana and Hong Kong.
The UK Health Security Agency said that no cases of the
variant had been detected in Britain and they were in contact
with South African colleagues over their data.
(Reporting by Alistair Smout
Editing by William Schomberg)