TLDRUpFront: Our mental-model on whether a country is
containing the contagion, facing an outbreak, or containing the outbreak
can be informed with these charts. We use WHO Daily Situation Reports,
and the “outbreak” baseline of China to compare and monitor 35
countries across 7 regions. Bookmark this page and revisit as we’ll be
updating data every few days.
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FullContextInTheBack: The last InfoMullet article on
COVID-19 introduced two mental-models on COVID-19 contagion of
“outbreak” and containment. With more complete data from a WHO
investigation of the Chinese outbreak and additional research by the
University of Washington we can now locate a threshold zone of risk for
the outbreak mode. This allows us to chart countries by region for both
total cases and daily rate of change in new cases, comparing them to the
China “outbreak” behavior.
Understanding the Charts
This is a quick overview for a lay reader to understand the charts. Or
you can skip reading this, go to a chart, post it on Twitter claiming
it’s proof of the zombie apocalypse and my sister will get mad at me. So
please don’t do that. For a fuller technical description of how we
calculated thresholds of risk see “Even More Context in the Way Back”
section after the regional data.)
For each Region we’ve displayed two charts for select countries: total
cases and the daily rate of change. The charts are aligned across the
horizontal axis so they all begin at the first day a case was confirmed.
This helps compare the behavior of a contagion to another country even
if they happened at different times. For example asking “How is my
country faring in response or containment at this point in time versus
China?” This isn’t just for curiosity sake – countries that fare better
containing outbreaks as they happen such as Singapore and South Korea
probably have methods we should look at replicating. Plus China
appears to have gone through a full outbreak cycle of growth and
collapse having now contained the spread. This took about ~65 days and
gives us a lifecycle baseline to compare other countries too. Finally
pay attention that in the total cases chart, the vertical axis is a
logarithmic scale of base ten, so that countries with cases ranging from
under 10 to nearly 100,000 can be displayed on the same chart. But
don’t misread a line “half-way” up the chart as being halfway to 100,000
– it’s closer to 1,000. What this means is you could still add all the
confirmed cases world wide and they probably wouldn’t equal half of
what China has already experienced, which is an important sanity check
to keep in mind.
Whether a contagion is being contained or faces an outbreak, or whether
an outbreak is being contained can be understood by several means.
First, the steepness of the line as it passes through the threshold of
risk. If it is a steep line – as seen in China, Italy, and Iran – then
chances of an outbreak that are difficult to contain are high. But if
the growth line is mostly flat as it enters the threshold of risk or
never reaches the threshold it indicates there may be containment. Both
Japan and Singapore show this example.
Even if a country has had an outbreak behavior, when we begin to see the
growth line in total cases flatten out and the daily rate of change
drop, such as in South Korea, that’s a good indication the contagion has
been contained.
Finally, although total cases tell us where we’ve been, the daily rate
of change tells us where we’re going. If the daily rate of change is
increasing upward that’s a sign the contagion is accelerating. But if
it’s declining, that’s a sign the contagion is being contained. This
data however can be very ‘noisy’ in the early stages when there are few
cases, so a growth rate of 100-200% might occur if the country got its
testing act together.
Caveat Lector the Deuce
Same caveats apply as the last article. This is intended to improve
mental models and not for peer review. Specifically we are only charting
the data the WHO provides in it’s Daily Situation Reports.(1) This
means if a country is actively suppressing information it may not look
bad until it is bad. Lack of available testing kits may also make some
countries look “better” than others that are testing more people, and
catching more cases. This data should be treated as notional and
illustrative. And keep in mind that even in the cases of an outbreak we
know from China what that looks like and have conducted forecasts within
ambiguity for the United States, an “outbreak” does not mean the zombie
apocalypse has arrived. Just that containing the contagion is going to
prove very difficult until it burns itself out.
COVID-19 by Region
North America
We’ll start with North America. As of today, it looks like the United
States could be heading to an outbreak behavior. Bear in mind however
that this aggregates all the United States into one country and with the
geographic expanse we could combining several containable contagions
into one number that looks at outbreak. On the other hand, conflicting
guidelines on who should be tested, and a lack of testing kits for the
early part of the crisis may mean that across the board cases are being
systemically under reported.
Northern Europe
Outside of China, Europe is struggling the most to contain the
contagion. In Northern Europe Germany is crossing the threshold risk
with BeNeLux (Belgium, Netherlands, and Luxemborg) and Nordic countries
(Iceland, Findland, Sweden, Norway, Denmark, and Greenland) not far
behind entering the same risk area. This is worrying because BeNeLux and
the Nordic countries are a fraction of the size of Germany, so
comparatively they are getting hit worse. However, they may also be
reporting more cases because they have more testing kits and are being
more expansive in their testing protocols – so bear that in mind.
Southern Europe
Southern Europe, especially Italy, are struggling to contain the
contagion. Italy’s recent measures of mass quarantines are being widely
reported and the chart shows why. Italy’s growth entered the risk
threshold and has already cleared it and is still growing strong.
France, Spain, and Switzerland are also now in, or entering, the risk
zone, all with steep growth which implies they will enter an outbreak
mode.
South Asia
There aren’t many confirmed cases in South Asia. Singapore demonstrates
an excellent example of a contained outbreak. And India, Pakistan, and
Bangladesh are all reporting only a handful of cases. This could be
good news, that a combination of unfavorable environmental and
demographic conditions mitigates the spread. But given that these
countries also have massive populations, often living in close
proximity, and often with inadequate access to healthcare we’d caution
against too rosy an estimate. It may be that the contagions are just now
starting, or that cases and fatalities are not being reported, there’s
not enough testing available, governments are hiding numbers – or a
combination of all of the above.
East Asia
The first region struck by the contagion, East Asia provides an
excellent case study in comparing the behavior modes across the three
countries. South Korea had an outbreak but appears to be successfully
containing it at a level far below China’s, without resorting to
authoritarian measures. There’s a lot of good lessons to learn from
this. Japan doesn’t appear to be threatened by a breakout. Even as its
cases climb towards the risk threshold it’s at a fairly flat incline.
Middle East
The most hard-hit country in the Middle East is Iran. Interestingly it’s
behavior curve begins sooner in the outbreak cycle, and is steeper,
than China’s. This may be because of local factors but could also
represent the Iranian regime suppressing information until it could not
be hidden anymore. The GCC stands for the Gulf Cooperation Council which
includes Saudi Arabia, Kuwait, Qatar, Oman, Bahrain and the United Arab
Emirates.
South America
We’ve added South America as a placeholder – but there’s not much to
report yet as far as WHO Data is concerned. Brazil, Ecuador and
Argentina have less than 50 cases between them and other countries are
all in single digits.
Even More Context in the Way Back: Determining the Threshold of Risk
In the outbreak mode, in red marked #1, a contagion of daily new cases
grows exponentially at a high rate over time, but then collapses just as
quickly. For reasons discussed in our first article, the contagion
burns itself out. In a containment mode, marked with #3 , daily new
cases grow more slowly and diminish more gradually. The area under
either curve represents the total cases, which when plotted would appear
as an S-Curve.
We’ve now seen China go through this entire cycle as the first nation to
deal with COVID-19 and can plot their actual data to recreate the
hypothetical charts above.
One piece of key data we were missing until last week was where to
locate a threshold of risk to understand whether a contagion would
manifest in containment or outbreak mode. Researchers at the University
of Washington & the Fred Hutchinson Research center however compared
Seattle, WA to Wuhan (based on WHO Data) and found:
“We know that Wuhan went from an index case in ~Nov-Dec 2019 to several
thousand cases by mid-Jan 2020, thus going from initial seeding event to
widespread local transmission in the span of ~9-10 weeks. We now
believe that the Seattle area seeding event was ~Jan 15 and we’re now ~7
weeks later. I expect Seattle now to look like Wuhan around ~1 Jan,
when they were reporting the first clusters of patients with unexplained
viral pneumonia. We are currently estimating ~600 infections in
Seattle, this matches my phylodynamic estimate of the number of
infections in Wuhan on Jan 1. Three weeks later, Wuhan had thousands of
infections and was put on large-scale lock-down.”(2)
Note they are describing estimates of actual cases, not confirmed. Using
their timeline however we took the total confirmed cases reported in
China by WHO along their timeline and located the band centered at 800
confirmed cases in the top chart and 40% growth rate in the bottom
chart. The band extends up and down to represent both uncertainty and
differences between locations. It’s a notional indication at best, but
looking through the charts it does seem that those countries which cross
the band at a steep line end up in an outbreak pattern, while those who
avoid it or enter it on a flatter growth pattern have contained the
contagion.
Explicacion de Ignacio Martinez Lejarza Esparducer.:
Mientras
en China la evolución, desde el primer día con algún caso ,sigue un
crecimiento logístico "de libro" ,en la inmensa mayoría de los países,
se pasa por un cierto periodo de meseta, de entre 15 a 20 días, antes de
dispararse el crecimiento del contagio de forma algo más acelerada de
lo esperado. Muy pocos países ( Suiza y algún otro que no muestro y el
conocido de Irán) no presentan esta anomalía "mesetaria". Presentan otra
peor crecen "casi verticalmente" desde el principio. - ¿por qué la aceleración gradual habitual
que prevé la curva logística sólo se ha dado en China mientras en el
resto de paises se contiene 15 días y luego "explota" ? Me temo que China nos ha ganado por la mano. *Segun Ignacio es preocupante el "mesetarismo" este tan "peligroso". -
NOTA: La logística es una curva de evolución muy estudiada que crece
aceleradamente al principio pero hasta un punto a partir del cual que
empieza a crecer con ,cada vez menor aceleración, hasta que finalmente
deja "casi" de crecer. - Via del muro de Ignacio Martinez Lejarza Esparducer - RM:Este virus es nuevo, y no sabemos bien aun como se comporta, quizas se comporte de diferente forma en cada pais, quizas se expande de diferente forma
Characteristics
of and Important Lessons From the Coronavirus Disease 2019 (COVID-19) Outbreak
in ChinaSummary of a Report of 72 314 Cases From the Chinese Center for Disease
Control and Prevention
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