China’s cases of Covid-19 are finally declining. A WHO expert explains why.“It’s all about speed”: the most important lessons from China’s Covid-19 response.
^^^ interesting interview that offers some new understanding with some clear windows of opportunity. China’s response has been very impressive in many ways, but some characteristics of covid-19 help.
“...You look at the big, long lists of all the cases and identify those where you have clusterings in space and time and try to investigate what kind of clustering happened: Was it in a hospital, an old-age home, theaters, restaurants? We found it was predominantly in families. It’s not a big surprise; China had shut down a lot of the other ways people could gather. And family clusters are the closest, longest exposures [to the virus], and getting the virus is a function of whether someone’s got it, how long they’re exposed, and how much virus they are shedding.
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.”
cont.