COVID-19: interesting data from Korea and from the Diamond Princess

One of the first countries to deal with the epidemic was South Korea. Unlike China, South Korea is a fairly transparent society and data published by the Korean CDC (Center for Disease Control) can be more or less taken at face value.

A progress report is published every day on their website: here is today’s edition.

The most interesting part of the report is Table 5, which I am reproducing as a screenshot below:

Table 5 from the Korean CDC report, March 18, 2020

Let’s have a good look at this. Preliminary remark: Korea started a massive testing (according to Table 1 in the same report, nearly 300,000 people have been tested, at a current rate of 10,000 a day) and tracking program early, leveraging all available tech data — privacy concerns be darned.

Observation 1: overall mortality is 1 (one) percent. Still one percent too much, to be sure. But considerably lower than what has been reported from some other places — I suspect because of undertesting.

Observation 2: mortality in the 0-29 age bracket is nil — not one death out of 2,867 patients.

Observation 3: in the 30-49 age bracket, just two (2) deaths out of 2,044 patients, or about 0.1%. Only above 50 does mortality start rising, over 60 in a worrisome fashion. (Not coincidentally, so do comorbidities/pre-existing conditions. I would love to see the statistics broken down between otherwise healthy people and those with chronic cardiovascular/pulmonary/immunity/diabetes problems, or cancer patients. Hypertension is apparently another major risk factor.)

Observation 4: Note the interesting “gender gap”. Men (1.39%) have nearly twice the mortality of women (0.75%). I asked friends on Facebook familiar with South Korea, and they told me over half of men smoke, compared to fewer than five percent of women.

Now what can we expect for older people who are otherwise healthy? Chinese data (caveat lector) suggest overall mortality for patients without comorbidities may be about one-third the overall statistic. https://www.worldometers.info/coronavirus/coronavirus-age-sex-demographics/

And then there is the uncertainty factor of how many people are asymptomatic virus carriers. This is impossible to ascertain without a much more massive testing program (and this isn’t a test you can quickly do with a strip!), but I have seen estimates from 5-7 carriers for each overt disease case.

But the Diamond Princess cruise ship offers an interesting insight. It had nearly 4,000 people on board—many of them in risk groups. (Somebody who used to perform aboard cruise ships quipped that passengers are mostly “the newlywed and the nearly dead” ;)) You’d expect these packed together on a ship in quarantine to be all infecting each others. And yet… 4,061 passengers and crew were examined, on board what effectively became an unintentional virus incubator. Only 712 contracted the virus (about 17.5%), of which 334 asymptomatic (8.2% of the total), leaving 378 (9.3% of the total) ill. Only 7 people died (1.85% of those ill, or 0.17% of all passengers and crew examined), all of them age 70 or older. (Remember, the passenger population is skewed toward the elderly.)

One might treat Diamond Princess stats as an upper limit (since spreading in even dense urban areas will never be as efficient as on a cruise ship) and South Korea as what can be achieved with agile and efficient tracking and containment measures.

Meanwhile, a frantic search for both vaccines and drugs continues. One track that may yield results earliest is the repurposing of existing drugs following off-label testing, since safety and “therapeutic interval” testing have already been done for their original approval. I have mentioned a promising remdesivir trial and I see increasing reports that chloroquine (which has been used for decades as an antimalarial) may interferewith the virus lifecycle. (See e.g., https://www.ncbi.nlm.nih.gov/pubmed/32171740)

Be well, stay healthy, be prepared, and remember:

[L]et me assert my firm belief that the only thing we have to fear is fear itself — nameless, unreasoning, unjustified terror which paralyzes needed efforts to convert retreat into advance.

FDR, inaugural address (1933)

UPDATE: via Behind The Black,

(1) an article in SCIENCE about South Korea and how it got a “wake-up call” in 2015 when a businessman brought back MERS from the Middle East

(2) a lengthy analysis of the Diamond Princess data
(3) are there 6 asymptomatic or “too mild to notice” cases for each clinical case?

(4) https://www.statnews.com/2020/03/16/lower-coronavirus-death-rate-estimates/

UPDATE 2: computational biochemistry pioneer Michael Levitt (2013 Nobel Prize in Chemistry shared with Arieh Warshel and Martin Karplus) sounds an optimistic note based on what he knows. His comments start off with Israel (he divides his time between Weizmann and Stanford) but then go on to the rest of the world.

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