On 13/03/2020 15:49, Thomas Cox wrote:
> I'm a little confused by the graph.
>
> The graphs in the attached image don't appear to reflect exponential
> growth in confirmed cases, in fact some seem to curve down.
Yes. Apparently, the typical full function is not exponential but
sigmoidal. Not sure if the deviation from exponential is due to the
effects of behavour intervention or to the data hitting the start of the
linear section of the sigmoidal curve (or both).
As you can see, my expertise expired at "Apparently, ", so I am probably
just adding noise now.
> It seems right to compare the number of deaths to the number of cases at
> an earlier time, but I wonder if 14 days is adequate?
People on
> respirators might die long after two weeks from the point at which they
> were infected as might people on oxygen and less intensive interventions.
Yes. Presumably this is factored in within the Lancet paper I cited for
the estimate of 14 days.
>
> As well, while China moved rapidly to build new hospitals, and was able
> to provide equipment, supplies, and staff, thereby providing care for
> people who needed strong measures, I'm not sure most of the rest of the
> world is able, even if willing, to mobilize resources on the scale China
> did.
>
> The result would be an underestimation of deaths, especially for
> countries like Italy who cannot come close to China's performance in
> isolation, treatment, and quarantine.
Aye.
regards,
Jim
>
>
> Thomas Cox PhD RN
> [log in to unmask]
>
>
> On Friday, March 13, 2020, 11:16:05 AM EDT, Ball, William
> <[log in to unmask]> wrote:
>
>
> For those interested, the latest (13/3) figures
> <https://www.gov.uk/guidance/coronavirus-covid-19-information-for-the-public#number-of-cases> for
> testing in the UK are as follows:
>
> tested - 32,771
> confirmed - 798
> deaths - 10
>
> The linked page is official DoH and gets updated daily. Compared to
> other nations (as of 10/3
> <https://ourworldindata.org/covid-testing-10march>) we're not actually
> doing too badly, although still only around 1/10th the number of tests
> vs. South Korea.
>
> **Kind regards,
>
> Will
>
> ------------------------------------------------------------------------
> *From:* James V Stone <[log in to unmask]>
> *Sent:* 13 March 2020 14:35
> *To:* Ball, William <[log in to unmask]>; [log in to unmask]
> <[log in to unmask]>
> *Subject:* Re: oops: A simple calculation (hopefully wrong)
>
>
> CAUTION: This email originated from outside Edinburgh Napier University.
> Do not follow links or open attachments if you doubt the authenticity of
> the sender or the content.
>
> On 13/03/2020 13:07, Ball, William wrote:
> > Thanks for sharing James.
> >
> > The fact that we need to make such assumptions really highlights the
> > lack of certainty we currently have. I'd echo your sentiments around
> > testing - not only does a lack of testing result in overestimates for
> > mortality rates (potentially worrying people), but we risk allowing a
> > wider spread as unconfirmed cases may not isolate properly.
> >
> > One thing I have heard from medical colleagues is that there's a huge
> > lack of capacity in virology testing, meaning we have to strictly
> > prioritise who we can test (e.g. to identify non-cases in a hospital
> > environment). In that context, it really does make you wonder why wider
> > social isolation measures haven't been enforced?
> >
>
> Dear Will,
>
> That's interesting. I recall hearing that the government was going to
> ramp up testing:
>
> "This increases testing capacity to more than 1,000 people a day for
> England."
>
> Source: Published 7 February 2020.
> https://www.gov.uk/government/news/phe-novel-coronavirus-diagnostic-test-rolled-out-across-uk
>
> (I think a later update increased this further).
> It seems as if the government initially planned to test widely, but
> seems to have abandoned that idea, given current advice to just stay home.
>
> regards,
>
> Jim
>
> > **Kind regards,
> >
> > Will
> >
> > ------------------------------------------------------------------------
> > *From:* email list for Radical Statistics <[log in to unmask]> on
> > behalf of James V Stone <[log in to unmask]>
> > *Sent:* 13 March 2020 12:39
> > *To:* [log in to unmask] <[log in to unmask]>
> > *Subject:* oops: A simple calculation (hopefully wrong)
> >
> >
> > CAUTION: This email originated from outside Edinburgh Napier University.
> > Do not follow links or open attachments if you doubt the authenticity of
> > the sender or the content.
> >
> > (Oops, no change to conclusion, but forgot to include a factor of 800).
> >
> > --
> >
> > Yesterday, the government said there were probably 10,000 coronavirus
> > cases already, but did not give any indication of how that number was
> > estimated.
> >
> > In the absence of widespread testing, the only reliable data we have is
> > the number of deaths.
> >
> > I hesitate to send this, but if the government will not supply the
> > evidence for its strategy then people will do their best with the sparse
> > data available. Like this:
> >
> > ==
> >
> > Number of deaths=8 in UK as of 12th March 2020.
> >
> > Assumption: 8 deaths represents 1% of cases, which implies 8*100/1=800
> > cases (most of these deaths happened before 12th March, so the final
> > result below is an under-estimate).
> >
> > Assumption: Delay D=14 days between infection and death days.
> > This suggests there were 800 cases 14 days ago.
> > Source: Real estimates of mortality following COVID-19 infection
> >
> https://www.thelancet.com/journals/laninf/article/PIIS1473-3099(20)30195-X/fulltext
> >
> > Assumption: Rate of infection increase R=0.33 per day (probably an
> > over-estimate).
> > Sourc: Rate of increase in many countries; hopefully less in the UK, see
> > https://twitter.com/MarkJHandley, and attached graph for example.
> >
> > Taken together, this implies there are 800*(1+R)^D = 800*(1+0.33)^14 =
> > 43,352 cases today.
> >
> > ==
> >
> > I recognise all of this is based on minimal evidence and uncertain
> > assumptions. But if it is even roughly correct, the extrapolation from
> > over the next 30 days is worrying.
> >
> > So, here is my question: Why is the government not testing widely?
> >
> > Without having access testing data, who knows which part of the sigmoid
> > infection curve we are on at any given time?
> >
> > And, FYI I am not an epidemiologist, and I'd really like to be wrong
> > about almost everything above.
> >
> > regards,
> >
> > Jim Stone
> >
> >
> > --
> > James V Stone
> > Honorary Associate Professor,
> > Sheffield University, UK.
> > Web: sebtelpress.com
> > Twitter: @jgvfwstone
> >
> >
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> --
> James V Stone
> Honorary Associate Professor,
> Sheffield University, UK.
> Web: sebtelpress.com
> Twitter: @jgvfwstone
>
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--
James V Stone
Honorary Associate Professor,
Sheffield University, UK.
Web: sebtelpress.com
Twitter: @jgvfwstone
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