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* South Africa puts AstraZeneca vaccinations on hold
* Study: shot gives minimal protection against mild
infection
* Britain says Astra shot stops death and severe illness
* Concerns rise over longer fight against virus
(Adds AstraZeneca and geography of South African variant,
Australian and French comment)
By Guy Faulconbridge and Kate Holton
LONDON, Feb 8 (Reuters) - South Africa halted Monday's
planned rollout of AstraZeneca's COVID-19 vaccinations after
data showed it gave minimal protection against mild infection
from one variant, stoking fears of a much longer cat-and-mouse
battle with the pathogen.
The coronavirus has killed 2.3 million people and turned
normal life upside down for billions but new variants have
raised fears that vaccines will need to be tweaked and people
may have to have booster shots.
Researchers from the University of Witwatersrand and the
University of Oxford said in a prior-to-peer analysis that the
AstraZeneca vaccine provided minimal protection against mild or
moderate infection from the South African variant among young
people.
"This study confirms that the pandemic coronavirus will find
ways to continue to spread in vaccinated populations, as
expected," said Andrew Pollard, chief investigator on the Oxford
vaccine trial.
"But, taken with the promising results from other studies in
South Africa using a similar viral vector, vaccines may continue
to ease the toll on health care systems by preventing severe
disease."
Britain and Australia urged calm, citing evidence that the
vaccines prevented grave illness and death, while AstraZeneca
said it believed its vaccine could protect against severe
disease.
But if vaccines do not work as effectively as hoped against
new and emerging variants, then the world could be facing a much
longer - and more expensive - battle against the virus than
previously thought.
The AstraZeneca vaccine was the big hope for Africa as it is
cheap and easier to store and transport than the Pfizer shot,
making South Africa's move a major blow, with sweeping
implications for other regions.
The so called South African variant, known by scientists as
20I/501Y.V2 or B.1.351, is the dominant one in South Africa and
is circulating in 41 countries around the world including the
United States.
Other major variants include the so-called UK variant, or
20I/501Y.V1, and the Brazilian variant known as P.1.
VACCINE SHOCK
An analysis of infections by the South African variant
showed there was only a 22% lower risk of developing
mild-to-moderate COVID-19 if vaccinated with the AstraZeneca
shot versus those given a placebo.
Protection against moderate-severe disease, hospitalisation
or death could not be assessed in the study of around 2,000
volunteers who had a median age of 31 as the target population
were at such low risk, the researchers said.
While thousands of individual changes have arisen as the
virus mutates on replication and evolves into new variants, only
a tiny minority are likely to be important or change the virus
in an appreciable way, according to the British Medical Journal.
While the lead investigator on the trial said that recent
data indicated that protection against severe disease was likely
from the vaccine, the study raised the prospect of repeated
vaccination against a changing virus.
Professor Shabir Madhi, lead investigator on the AstraZeneca
trial in South Africa, said the vaccine's similarity to another
produced by Johnson & Johnson, which reduced severe disease by
89%, suggested it would still prevent serious illness or death.
"There's still some hope that the AstraZeneca vaccine might
well perform as well as the Johnson & Johnson vaccine in a
different age group demographic that I address of severe
disease," he told BBC radio.
Sarah Gilbert, professor of vaccinology at the University of
Oxford, said efforts were under way to develop a new generation
of booster shot vaccines that will allow protection against
emerging variants.
"This is the same issue that is faced by all of the vaccine
developers, and we will continue to monitor the emergence of new
variants that arise in readiness for a future strain change,"
she said.
STOPS DEATH
British junior health minister Edward Argar said the
AstraZeneca vaccine prevents death and serious illness and is
effective against the main variants of the virus in the United
Kingdom, though people may have to have a booster shot as it
mutates.
He echoed Australia which is expected approve the use of the
AstraZeneca vaccine within days.
"There is currently no evidence to indicate a reduction in
the effectiveness of either the AstraZeneca or Pfizer vaccines
in preventing severe disease and death. That is the fundamental
task, to protect the health," Health Minister Greg Hunt said.
Argar said just 147 people had been known to have been
infected with the South African variant in Britain, though he
allowed that booster shots - such as against the common flu -
might be needed in future.
"It would just be normal, in a sense, as we did with the flu
vaccine, to update it to catch anything the virus is trying to
do to keep ahead of it."
French Health Minister Olivier Veran said he continued to
support the AstraZeneca vaccine, arguing it provided sufficient
protection against "nearly all the variants".
(Reporting by Guy Faulconbridge and Kate Holton; editing by
Michael Holden, Angus MacSwan and Nick Macfie)
