THREAD
Let's look at COVID-19 case progression in South Korea.
South Korea's remarkable testing program (365,000 tested so far) continues to look effective at bending the curve, and the number of active cases continues to fall.
Though total cases continue to grow by ~100/day.
Let's look at COVID-19 case progression in South Korea.
South Korea's remarkable testing program (365,000 tested so far) continues to look effective at bending the curve, and the number of active cases continues to fall.
Though total cases continue to grow by ~100/day.
With a little bit of math it is possible to use the reported time series of cases, deaths, and recoveries to estimate the average case trajectory in South Korea.
In other words, from the time someone is diagnosed how long does it take for the case to be resolved.
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In other words, from the time someone is diagnosed how long does it take for the case to be resolved.
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First, a word of caution, these empirical estimates of case progression are less precise and reliable than doing a comprehensive case review; however, available case progression data has mostly been limited to small samples right now, e.g. thelancet.com/action/showPdf…
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So what is the empirically estimated case progression telling us?
Firstly, COVID-19 is not a particularly quick illness. After diagnosis, <10% of patients clear the virus within 2 weeks. Though ~75% will recover within 25 days.
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Firstly, COVID-19 is not a particularly quick illness. After diagnosis, <10% of patients clear the virus within 2 weeks. Though ~75% will recover within 25 days.
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With that profile, if a government's primary response is a generalized shutdown, then it will likely take many weeks to interrupt transmission.
Though with widespread testing and targeted isolation, that timetable can probably be accelerated.
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Though with widespread testing and targeted isolation, that timetable can probably be accelerated.
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Another important point, people in South Korea are still dying 3 and 4 weeks after being diagnosed with COVID-19.
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A couple of weeks ago, people were excited that South Korea was only showing a 0.6% case-fatality rate.
Today that rate has risen to 1.4%, and the progression analysis suggests that it could still rise over 2%.
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Today that rate has risen to 1.4%, and the progression analysis suggests that it could still rise over 2%.
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Because South Korea has tested extensively, they provide one of the best benchmarks of COVID-19's true mortality rate. If South Korea's case-fatality rate really does climb over 2%, that will be a grim prediction for the rest of the world.
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