Dr. John Lee, How deadly is the coronavirus? It’s still far from clear
In
announcing the most far-reaching restrictions on personal freedom in
the history of our nation, Boris Johnson resolutely followed the
scientific advice that he had been given. The advisers to the government
seem calm and collected, with a solid consensus among them. In the face
of a new viral threat, with numbers of cases surging daily, I’m not
sure that any prime minister would have acted very differently.
But
I’d like to raise some perspectives that have hardly been aired in the
past weeks, and which point to an interpretation of the figures rather
different from that which the government is acting on. I’m a
recently-retired Professor of Pathology and NHS consultant pathologist,
and have spent most of my adult life in healthcare and science – fields
which, all too often, are characterised by doubt rather than
certainty. There is room for different interpretations of the current
data. If some of these other interpretations are correct, or at least
nearer to the truth, then conclusions about the actions required will
change correspondingly.
The
simplest way to judge whether we have an exceptionally lethal disease
is to look at the death rates. Are more people dying than we would
expect to die anyway in a given week or month? Statistically, we would
expect about 51,000 to die in Britain this month. At the time of
writing, 422 deaths are linked to Covid-19 — so 0.8 per cent of that
expected total. On a global basis, we’d expect 14 million to die over
the first three months of the year. The world’s 18,944 coronavirus
deaths represent 0.14 per cent of that total. These figures might shoot
up but they are, right now, lower than other infectious diseases that we
live with (such as flu). Not figures that would, in and of themselves,
cause drastic global reactions.
Initial
reported figures from China and Italy suggested a death rate of 5 per
cent to 15 per cent, similar to Spanish flu. Given that cases were
increasing exponentially, this raised the prospect of death rates that
no healthcare system in the world would be able to cope with. The need
to avoid this scenario is the justification for measures being
implemented: the Spanish flu is believed to have infected about one in
four of the world’s population between 1918 and 1920, or roughly 500
million people with 50 million deaths. We developed pandemic emergency
plans, ready to snap into action in case this happened again.
At
the time of writing, the UK’s 422 deaths and 8,077 known cases give an
apparent death rate of 5 per cent. This is often cited as a cause for
concern, contrasted with the mortality rate of seasonal flu, which is
estimated at about 0.1 per cent. But we ought to look very carefully at
the data. Are these figures really comparable?
Most
of the UK testing has been in hospitals, where there is a high
concentration of patients susceptible to the effects of any infection.
As anyone who has worked with sick people will know, any testing regime
that is based only in hospitals will over-estimate the virulence of an
infection. Also, we’re only dealing with those Covid-19 cases that have
made people sick enough or worried enough to get tested. There will be
many more unaware that they have the virus, with either no symptoms, or
mild ones.
But
there’s another, potentially even more serious problem: the way that
deaths are recorded. If someone dies of a respiratory infection in the
UK, the specific cause of the infection is not usually recorded, unless
the illness is a rare ‘notifiable disease’. So the vast majority of
respiratory deaths in the UK are recorded as bronchopneumonia,
pneumonia, old age or a similar designation. We don’t really test for
flu, or other seasonal infections. If the patient has, say, cancer,
motor neurone disease or another serious disease, this will be recorded
as the cause of death, even if the final illness was a respiratory
infection. This means UK certifications normally under-record deaths due
to respiratory infections.
Now
look at what has happened since the emergence of Covid-19. The list of
notifiable diseases has been updated. This list — as well as containing
smallpox (which has been extinct for many years) and conditions such as
anthrax, brucellosis, plague and rabies (which most UK doctors will
never see in their entire careers) — has now been amended to include
Covid-19. But not flu. That means every positive test for Covid-19 must
be notified, in a way that it just would not be for flu or most other
infections.
In
the current climate, anyone with a positive test for Covid-19 will
certainly be known to clinical staff looking after them: if any of these
patients dies, staff will have to record the Covid-19 designation on
the death certificate — contrary to usual practice for most infections
of this kind. There is a big difference between Covid-19 causing death,
and Covid-19 being found in someone who died of other causes. Making
Covid-19 notifiable might give the appearance of it causing increasing
numbers of deaths, whether this is true or not. It might appear far more
of a killer than flu, simply because of the way deaths are recorded.
If
we take drastic measures to reduce the incidence of Covid-19, it
follows that the deaths will also go down. We risk being convinced that
we have averted something that was never really going to be as severe as
we feared. This unusual way of reporting Covid-19 deaths explains the
clear finding that most of its victims have underlying conditions — and
would normally be susceptible to other seasonal viruses, which are
virtually never recorded as a specific cause of death.
Let
us also consider the Covid-19 graphs, showing an exponential rise in
cases — and deaths. They can look alarming. But if we tracked flu or
other seasonal viruses in the same way, we would also see an exponential
increase. We would also see some countries behind others, and striking
fatality rates. The United States Centers for Disease Control, for
example, publishes weekly estimates of flu cases. The latest figures
show that since September, flu has infected 38 million Americans,
hospitalised 390,000 and killed 23,000. This does not cause public alarm
because flu is familiar.
The
data on Covid-19 differs wildly from country to country. Look at the
figures for Italy and Germany. At the time of writing, Italy has 69,176
recorded cases and 6,820 deaths, a rate of 9.9 per cent. Germany has
32,986 cases and 157 deaths, a rate of 0.5 per cent. Do we think that
the strain of virus is so different in these nearby countries as to
virtually represent different diseases? Or that the populations are so
different in their susceptibility to the virus that the death rate can
vary more than twentyfold? If not, we ought to suspect systematic error,
that the Covid-19 data we are seeing from different countries is not
directly comparable.
Look
at other rates: Spain 7.1 per cent, US 1.3 per cent, Switzerland 1.3
per cent, France 4.3 per cent, South Korea 1.3 per cent, Iran 7.8 per
cent. We may very well be comparing apples with oranges. Recording cases
where there was a positive test for the virus is a very different thing
to recording the virus as the main cause of death.
Early
evidence from Iceland, a country with a very strong organisation for
wide testing within the population, suggests that as many as 50 per cent
of infections are almost completely asymptomatic. Most of the rest are
relatively minor. In fact, Iceland’s figures, 648 cases and two
attributed deaths, give a death rate of 0.3 per cent. As population
testing becomes more widespread elsewhere in the world, we will find a
greater and greater proportion of cases where infections have already
occurred and caused only mild effects. In fact, as time goes on, this
will become generally truer too, because most infections tend to
decrease in virulence as an epidemic progresses.
One
pretty clear indicator is death. If a new infection is causing many
extra people to die (as opposed to an infection present in people who
would have died anyway) then it will cause an increase in the overall
death rate. But we have yet to see any statistical evidence for excess
deaths, in any part of the world.
Covid-19
can clearly cause serious respiratory tract compromise in some
patients, especially those with chest issues, and in smokers. The
elderly are probably more at risk, as they are for infections of any
kind. The average age of those dying in Italy is 78.5 years, with almost
nine in ten fatalities among the over-70s. The life expectancy in Italy
— that is, the number of years you can expect to live to from birth,
all things being equal — is 82.5 years. But all things are not equal
when a new seasonal virus goes around.
It
certainly seems reasonable, now, that a degree of social distancing
should be maintained for a while, especially for the elderly and the
immune-suppressed. But when drastic measures are introduced, they should
be based on clear evidence. In the case of Covid-19, the evidence is
not clear. The UK’s lockdown has been informed by modelling of what
might happen. More needs to be known about these models. Do they correct
for age, pre-existing conditions, changing virulence, the effects of
death certification and other factors? Tweak any of these assumptions
and the outcome (and predicted death toll) can change radically.
Much
of the response to Covid-19 seems explained by the fact that we are
watching this virus in a way that no virus has been watched before. The
scenes from the Italian hospitals have been shocking, and make for grim
television. But television is not science.
Clearly,
the various lockdowns will slow the spread of Covid-19 so there will be
fewer cases. When we relax the measures, there will be more cases
again. But this need not be a reason to keep the lockdown: the spread of
cases is only something to fear if we are dealing with an unusually
lethal virus. That’s why the way we record data will be hugely
important. Unless we tighten criteria for recording death due only to
the virus (as opposed to it being present in those who died from other
conditions), the official figures may show a lot more deaths apparently
caused by the virus than is actually the case. What then? How do we
measure the health consequences of taking people’s lives, jobs, leisure
and purpose away from them to protect them from an anticipated threat?
Which causes least harm?
The
moral debate is not lives vs money. It is lives vs lives. It will take
months, perhaps years, if ever, before we can assess the wider
implications of what we are doing. The damage to children’s education,
the excess suicides, the increase in mental health problems, the taking
away of resources from other health problems that we were dealing with
effectively. Those who need medical help now but won’t seek it, or might
not be offered it. And what about the effects on food production and
global commerce, that will have unquantifiable consequences for people
of all ages, perhaps especially in developing economies?
Governments
everywhere say they are responding to the science. The policies in the
UK are not the government’s fault. They are trying to act responsibly
based on the scientific advice given. But governments must remember that
rushed science is almost always bad science. We have decided on
policies of extraordinary magnitude without concrete evidence of excess
harm already occurring, and without proper scrutiny of the science used
to justify them.
In
the next few days and weeks, we must continue to look critically and
dispassionately at the Covid-19 evidence as it comes in. Above all else,
we must keep an open mind — and look for what is, not for what we fear
might be.
John Lee is a recently retired professor of pathology and a former NHS consultant pathologist.
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