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 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.
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 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)
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