Post by Pancho Post by Pamela Post by Pancho Post by Pancho
I wouldn't put this down as a BoJo failure, more a case of adjusting
policy as new information comes to light.
Good that you found the Imperial College paper useful. It had an
instrumental effect on UK and US policy as soon as it was published. I
guess you've also seen Pueyo's "Hammer and Dance" page.
Never heard of Pueyo. I will have a look but there is a slight suspicion
he is an Elon Musk type science populist. Rather than a boring data
type. I will however give him a longer read.
From Pueyo, I see Bill Gates is also questioning the Imperial paper
parameters as too negative. Obviously Bill isn't an expert either and
not being an expert myself, I'm reluctant to question Neil Ferguson but
I just can't get the doubt out of my head. So maybe I'm just falling
prey to confirmation bias.
Bill Gates is well informed from his institute and general interest in
diseases and I would tend to go along with him. However the key
for the spread of Covid is the transmission rate and a spokesman was saying
today that it is 2.5 to 3.0, whereas Imperial College uses the much more
positive range of 2.0 to 2.4. That is a big difference and not in the
direction Gates is suggesting.
I'm not sure where you are going with that. We know the transmission
rate can be successfully reduced by the various interventions described
in the paper.
The question in my mind was the infection fatality rate (IFR)(and
similar rate for patients requiring ICU care). These are the figures
which dictate the feasibility of herd immunity (cost in human life, if
you like). There is clearly a debate going on that we aren't hearing.
Politicians can't admit openly that they are willing to let many tens of
thousands of people die in order to save the economy.
My suspicion is that Boris, Dom, et al were willing to let maybe 100,000
die in order to get herd immunity, i.e the mitigation strategy. Even
then this would probably still end with a limited herd immunity that
still had to be augmented with additional but much less extreme (less
economically costly) interventions to reduce transmission.
However, the Imperial paper suggested it would be worse than this.
It is even possible that Bojo's current strategy is still mitigation.
Boris may even just be keeping his options open for a few weeks,.
Trump seems more willing to openly stick to the mitigation strategy.
So we have a couple of interesting things to look out for. How it goes
in the US and what happens in China as it starts to relax social distancing.
If I were a betting man I would bet on Trump. However my view don't
count for diddly squat.
Post by Pamela
If you are up for looking into detail, what I don't understand is why on
Table 3 on page 9 of the Imperial College report,
"home isolation plus home quarantine" ("CI_HQ") gives a better result than
"home isolation plus home quarantine plus social distancing"
The top line of table 3 shows 53% (green) versus 33% (yellow). Other
are below the top line in the chart.
Table A1 in the appendix (page 20) of the report shows numerical number of
deaths, as opposed to relative impact shown in Table 3. Table A1 is
essentially the numerical equivalent of Table 3 but the colouring of severity
is quite different.
What am I missing?
Once interventions are relaxed (in the example in Figure 3, from
September onwards), infections begin to rise, resulting in a predicted
peak epidemic later in the year. The more successful a strategy is at
temporary suppression, the larger the later epidemic is predicted to be
in the absence of vaccination, due to lesser build-up of herd immunity.
So you are missing the assumption that interventions are for three
months only. During that three months we would want to build as much
herd immunity as possible without swamping the hospitals. In the extreme
case if we suppress transmission to virtually nil, we don't build any
herd immunity and it is just as if we are starting from scratch, with no
interventions, but three months later.
Sorry I just realised I answered you first question, but not you second.
The colouring is rather arbitrary. Consistency only really means the
relative ordering should be the same in any single table. Also arbitrary
either of the two categories (deaths of peak beds). R0 = 2.4 will give a
reductions are the same. In effect this is just because R0=2.4 just
means more death all round.
So the tables on page 9 and page 20 are apples and oranges. I'm afraid.