by
Les May
DURING
the Apollo 8 mission to the moon one of the crew, Jim Lovell, pressed
the wrong button on the flight computer. That cleared the memory
which held the data about the exact position and orientation of the
command module. As a result the flight computer ‘thought’
it was still on the launch pad so instead of the nose pointing
forward along the flight path, it pointed more or less at right
angles. Using the astro-sextant to make sightings on various stars
the crew were able to give the computer enough data to allow it to
figure out the orientation of the module.
Getting
back to Earth safely wasn’t
magic or good luck, it followed from the fact that the physics of
space flight
is an exact science obeying the
laws of
motion formulated by Sir
Isaac Newton in the seventeenth century. Knowing
the mass, velocity and the forces acting on an object we can predict
exactly where it will be at any time in the future.
Like
ecology, economics, politics and sociology, epidemiology is not an
exact science. It uses the tools of science to analyse its data,
presents its findings in numerical form and runs computer
simulations, but unlike physics, it is not an exact science. Its
predictions are ‘educated
guesses’ based upon
the collective
experiences of it’s practitioners.
Those experiences come
from investigating past
outbreaks of some pestilence. The educated guesses are in the form
of ‘this is what
happened last time with
a similar disease’.
The
UK government could truthfully say it was being ‘led
by the science’
so long as we were in the ‘containment
phase’ of dealing
with the spread of
SARS-CoV-2,
the name of the virus
which causes the disease COVID-19.
Containment worked with
the original
outbreak of the first human transmissable SARS
virus which was
eventually brought under control in July 2003, following a policy of
isolating people suspected of carrying
it and screening all
passengers travelling by air from affected countries for signs of the
infection. It has also
worked with outbreaks of Ebola, so it is a tried and tested method.
That phase is passed.
From now on the
decisions are political ones.
As
I understand the situation the government is assuming that about 60%
to 70% of the UK population will become infected with SARS-CoV-2 and
suffer from COVID-19, and that those that recover
will resist further infection so the virus will die out, an
assumption based upon the concept of ‘herd
immunity’.
Now
lets put some figures to this. The present population of the UK is
about 60 millions. If we take the conservative estimate of a 60%
infection rate that means that some 36 million people will be
infected. According
to the World
Health Organisation
(WHO)
the
crude mortality rate
(the number of reported deaths divided by the number
of reported
cases) is between 3-4%, (the
Chinese experience suggests 3.9%), but
the
infection mortality rate (the number of reported deaths divided by
the number of infections) will be lower. Assuming
that
it is in the regions of 1% that suggests 360,000 deaths can be
expected in the the
UK in the space
of a few months.
What
I find remarkable is that the UK government seems so complacent about
the spread of the virus. Compare this with the situation in China
where there have so far been 82,000 cases reported and 3,200 deaths
in a population of 1.4 billion people. (Figures correct at 13 March
2020)
Just
because the UK government has decided that the spread of the virus
can no longer be contained does not mean that we as individuals have
to fall in with this view. Older people in particular can to a large
extent avoid placing themselves in a position where they might
become infected, by avoiding meeting groups of people in confined
spaces. This
isn’t ‘panic’
it is rational behaviour.
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