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* Reuters' vaccine tracker: https://tmsnrt.rs/3zr9NFl
By Alistair Smout
LONDON, June 15 (Reuters) - British Prime Minister Boris
Johnson on Monday delayed by a month his plans to lift the last
COVID-19 restrictions in England after modelling showed that
thousands more people might die due unless reopening was pushed
back.
The move was due to the rapid spread of the Delta
coronavirus variant, which is more transmissible, associated
with lower vaccine effectiveness against mild disease and could
cause more hospitalisations in the unvaccinated.
He said the extra time would be used to speed up Britain's
vaccination programme - already one of the world's furthest
advanced - with two thirds of the population expected to have
had two shots by July 19.
Here are the details behind the decision:
WHAT AND WHO ARE THE MODELS AND THE MODELLERS?
Models commissioned by the government showed that without a
delay to the planned June 21 reopening, in some scenarios
hospitalisations could match previous peaks in cases when
ministers feared the health system could be overwhelmed.
Three models, made by the London School of Hygiene and
Tropical Medicine, Imperial College London and the University of
Warwick, fed into the government's pandemic modelling subgroup
SPI-M-O.
All three found that a delay would lower the peak of a new
wave fuelled by the Delta variant. A two-week extension would
have a significant effect, but four weeks would reduce the peak
in hospital admissions by around a third to a half, SPI-M-O
said.
SPI-M-O will make fresh projections before July 19 when the
full reopening is now expected to take place, with Johnson
saying that he does not want to delay reopening again.
WHAT ABOUT THE VACCINES?
Britain has one of the fastest vaccine rollouts in the
world, with over half of adults receiving both doses and more
than three quarters receiving at least one, which has led some
to question why restrictions need to be extended.
The modellers warned that while protection from vaccines was
not perfect, without them, England would be heading back into
lockdown.
Imperial epidemiologist Anne Cori told reporters that
differences in who was eligible, in rates of uptake, and the
fact that vaccine effectiveness was not 100%, all combined to
create the possibility of a large wave of hospitalisations.
VACCINE AND DELTA
One worrying aspect of the Delta variant is evidence that it
reduces protection from vaccines against symptomatic infection,
although experts still hoped it would work against severe
disease.
As Johnson announced the postponement, Public Health England
published data showing shots made by Pfizer and
AstraZeneca offer high protection against
hospitalisation from the variant identified in India of 96% and
92% respectively after two doses.
Asked if that data, released after the models were made,
would have an impact on the projections, Cori said they had used
different efficacy assumptions for their models, and PHE figures
would help to narrow down the range of likely scenarios.
"The optimistic vaccine efficacy or perhaps the central
(scenarios) are definitely more likely than the most pessimistic
set of vaccine efficacies we had looked at," she said.
WHAT ARE THE SOCIAL-ECONOMIC COSTS?
Many lawmakers in Johnson's own party expressed dismay at
the delay, with Steve Baker saying some people "increasingly
believe they are never going to see true freedom again".
Kevin McConway, emeritus professor of applied statistics at
The Open University, said the delay would buy time to learn more
about the Delta variant, and get more shots in arms.
But he said increased risks of opening on June 21 were hard
to quantify, and economic costs were not being modelled with
anywhere near the same rigour.
"I do wonder how the government can make good decisions on
the balance between restrictions on what we can do, if they have
detailed modelling of infections, vaccines, hospitalisations and
deaths (including information on the likely uncertainties), but
no detailed modelling (that I’ve seen) on the economic and
social costs of the restrictions," he said.
(Reporting by Alistair Smout;
Editing by Josephine Mason and Alison Williams)
