The benefit in terms of estimated lives saved
Suppose that a group of people who each had expected quality-adjusted
remaining years of life of 5 years, and who might have died with the
virus, has been spared that because of government restrictions (“the
lockdown”). We will assume that the benefit of the restrictions that
prevented such deaths are the value of 5 quality-adjusted years of life
multiplied by the number of lives saved. The NICE £30,000 threshold is
an assessment of the (maximum) resource cost that would be justified for
the UK health service to make an expected saving of one quality-adjusted
year of life. To save 5 QALY would be worth up to £150,000.
We apply this figure of £150,000 (or a figure of £300,000 if we make no
adjustment for co-morbidities and take 10 life years lost per death) to
estimates of the possible number of lives saved as a result of lockdowns
to give an overall benefit number. We compare that aggregate number with
an estimate of the lost resources from the lockdown. As noted above
there is no single, reliable estimate of lives that have been saved by
the UK lockdown and nor is there a widely accepted single figure for the
comprehensive overall cost of the lockdown (which should include lost
and damaged lives into the future as a result of severe restrictions and
not just lost incomes in 2020). So we present a range of estimated costs
and benefits based on a wide range of assumptions that we think
encompass plausible upper and lower limits on both costs and benefits.
At the high end of estimated lives saved is the difference between the
projected deaths from the study of Professors Ferguson’s group at
Imperial assuming no change in behaviour (500,000) (1) less an estimate
of excess UK deaths (approximately 60,000 by June 2020). This 440,000
net lives saved number is likely to be a significant overestimate of
likely lives saved. As noted above it does not account for changes in
behaviour that would have occurred without the government lockdown; it
does not count future higher deaths from side effects of the lockdown
(extra cancer deaths for example); it does not allow for the fact that
some of those “saved” deaths may just have been postponed because when
restrictions are eased. In the absence of a vaccine or of widespread
immunity, deaths may pick up again. (If the epidemic is dying out anyway
those deaths will not come as the lockdown is eased but in this case,
the 440,000 saved lives are also excessive because the lockdown may have
come as a decline in infections was happening for other reasons).
At the other end of the spectrum would be estimates of net saved lives
that are effectively zero. We set the lowest estimated net set lives
well above that and use (rather arbitrarily) a “lowest” estimate of
20,000.
For each life saved we apply a factor of either 5 or 10 quality-adjusted
extra years of life, each valued with the NICE guideline figure of
£30,000 (20).