China’s cases of Covid-19 are finally declining. A WHO expert explains why

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datum 2020/03/03
etiketter kina,who
url https://www.vox.com/2020/3/2/21161067/coronavirus-covid19-china
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Mörkertalet i Kina var litet. Dödligheten nära 1%.

"I think the key learning from China is speed — it’s all about the speed. The faster you can find the cases, isolate the cases, and track their close contacts, the more successful you’re going to be. Another big takeaway is that even when you have substantial transmission with a lot of clusters — because people are looking at the situation in some countries now and going, “Oh, gosh, what can be done?” — what China demonstrates is if you settle down, roll up your sleeves, and begin that systematic work of case finding and contact tracing, you definitely can change the shape of the outbreak, take the heat out of it, and prevent a lot of people from getting sick and a lot of the most vulnerable from dying. "

"More of a surprise, and this is something we still don’t understand, is how little virus there was in the much broader community. Everywhere we went, we tried to find and understand how many tests had been done, how many people were tested, and who were they.

In Guangdong province, for example, there were 320,000 tests done in people coming to fever clinics, outpatient clinics. And at the peak of the outbreak, 0.47 percent of those tests were positive. People keep saying [the cases are the] tip of the iceberg. But we couldn’t find that. We found there’s a lot of people who are cases, a lot of close contacts — but not a lot of asymptomatic circulation of this virus in the bigger population. And that’s different from flu. In flu, you’ll find this virus right through the child population, right through blood samples of 20 to 40 percent of the population. "

If you didn’t find the “iceberg” of mild cases in China, what does it say about how deadly the virus is — the case fatality rate?

"It says you’re probably not way off. The average case fatality rate is 3.8 percent in China, but a lot of that is driven by the early epidemic in Wuhan where numbers were higher. If you look outside of Hubei province [where Wuhan is], the case fatality rate is just under 1 percent now. I would not quote that as the number. That’s the mortality in China — and they find cases fast, get them isolated, in treatment, and supported early. Second thing they do is ventilate dozens in the average hospital; they use extracorporeal membrane oxygenation [removing blood from a person’s body and oxygenating their red blood cells] when ventilation doesn’t work. This is sophisticated health care. They have a survival rate for this disease I would not extrapolate to the rest of the world. What you’ve seen in Italy and Iran is that a lot of people are dying.

This suggests the Chinese are really good at keeping people alive with this disease, and just because it’s 1 percent in the general population outside of Wuhan doesn’t mean it [will be the same in other countries]."