China Covid Post-Wuhan : tiny numbers, mayhem of metrics and sources, and many insights for the world

We have started collecting China data from the beginning for the Expat Community project, now labelled "Solidarity Covid - Expats in China". We have never stopped collecting China data even when many around us in Shanghai want to just move on and forget about Covid. There’s no more back data available online for many metrics at most granular level, so we keep on collecting every day, even when it’s a boring yet reassuring 5 imported cases per day, because the value of our work stands in the continuity of our data.

In February, all the French community of Shanghai was frantically waiting for our Hubei / out of Hubei daily new cases graph showing the impact of the Wuhan early strict lockdown and soft lockdown outside of Hubei and celebrating the drop in nb of cases. By the last week of February (week 9) there were no more than 69 new cases outside of Hubei, vs 600 the week before, our 4000 readers were so supportive that we would bring them good news… We collected the data from the China official Health Department web site at prefecture level (over 300 with cases on 1200 prefectures) on a daily basis and could retrieve the back data by province on Wikipedia.

As the cases got scarcer and scarcer in mainland China, the data collection exercise got more and more complex. From March 1, it became impossible to export / copy / paste the data from that website, and overseas-imported cases appeared with some provinces reporting them as a separate territory. In others (Guangdong, Sichuan) imported cases were not differentiated from local cases, making it difficult to aggregate the import cases across provinces. From April 1 and the imminent lift of Wuhan’s 76-day long lockdown, the authorities of Hubei launched a large testing campaign to isolate lingering asymptomatic cases before lifting the lockdown after 7 days with no new cases. That was when the first asymptomatic cases were reported in Wuhan, 982 of them, and it would have been psychologically devastating to suddenly go from 0 new case to nearly 1000. Therefore those cases went into the new category of “asymptomatic” which was known of before but not monitored, considering asymptomatic cases can develop symptoms and hence become confirmed. The new category was yet not broken down by province in the official web site, but only reported as a national total. That’s when other Apps came into the game as they could provide some partial counts on those hard-to-fetch (yet not concealed, whatever the Western media may think) metrics on imported, asymptomatic (local or imported), severe and critical cases, and testing by province and prefecture. Sina, Alipay, Toutiao, Baidu, provincial Health Bureau websites are all apps that can only be downloaded with a China-based bank account, all in Chinese, and only on smartphone, which makes it complicated to structure into a database.

But with the help of native Chinese volunteers, we made the most complete non-governmental data set of Chinese cases collecting the local, imported cases, asymptomatic, severe and confirmed, by prefecture and by cluster and country of origin for imported cases. We have now 1200 WeChat China-based readers for our daily report combining the asymptomatic and confirmed cases. Non China-based people can collect the report every day on https://deeperin19coviddata.wordpress.com/analyses-quotidiennes/

After 8 months of curation of China data, I’m pretty confident about the China numbers now, there are sometimes rumors of cases, preventive school or residential compounds closures until testing is carried out again and again until re-confirmation, so new clusters are often reported 2-3 days after the 1st case is tested positive the first time. The data is just scattered across multiple sources and it looks like we are the only one to have structured it in a meaningful way, such as combining the asymptomatic and the confirmed cases by cluster, and segmenting the cases into relevant territories : end January we were the very first observers to breakdown China into Hubei / out of Hubei, now we have Wuhan / rest of Hubei / out of Hubei local / Imported in our CovidFlow list of territories https://eng.covidminute.com/covid-flow/, and the local cases are split again by cluster.

There is also a clinical value of differentiating the confirmed and asymptomatic cases. See the May episode in Wuhan : 1 month after the lockdown was lifted and as an average of 18 asymptomatic cases were found every day, an 89-old man was tested positive with symptoms after he was forced to go to hospital for testing. He had had some symptoms mid-March, didn’t get tested and had recovered. It was the first confirmed case in 60 days, but asymptomatic cases were still around. The interesting fact is that this old man infected 6 other people with symptoms whereas the 1000 asymptomatic cases picked up early April didn’t generate any symptomatic case, except for this old and fragile old man with underlying conditions. We’ve also had several Hubei / Xinjiang asymptomatic cases travel to other provinces by train, subway or car with other people and infecting no one or only asymptomatic, which can suggest the severity of the origin of the infection is a key factor in the development of the symptoms. 

So far we’ve had 5-6 clusters of local cases in China post Wuhan wave : The first ones were related to imported cases on the land Russian border and in Guangzhou, direct human contact for Guangzhou and possibly in Harbin, via a laundry shop that collected linen from quarantine passengers in Jilin.

The reaction of the authorities to these clusters was to reduce the risk of human transmission from overseas with a border closure for foreigners (including residents); abysmal cuts in flight schedules generating huge increases in airfares; testing upon arrival and quarantine for all incoming travelers, regardless of where they come from. We have all been victims of this: Chinese nationals living overseas, foreign residents, whether stuck in our home countries or safe in China, being separated from our families and businesses has had a huge impact on our lives.

After the Russian border clusters, we had 4 clusters related to fresh / frozen / living meat / fish / animals echoing the clusters found in several countries in slaughterhouses. All of them were under control (no new cases) in 8 to 34 days with massive testing and strict quarantine of 28 days in the affected compounds, main objective is to avoid the spread of the infection, see below the table on the distribution of clusters by prefecture, cases outside were very limited, thanks again to the GPS tracking of contacts.

After the Xinfadi outbreak, at a huge market supplying fresh food for the whole city of Beijing, 29 000 visitors / staff of the market were screened and tested, of which 91 were in Shanghai. The focus was on identifying the source of the infection. Over 40 days, samples of frozen / fresh Imported animal food were tested and the virus was found on samples across 9 provinces on the various items like frozen shrimp from Ecuador and frozen chicken wings from Brazil. Not all of them generated human cases in China, and in the case of the outbreaks, the virus was transmitted first to people who manipulated the food during the packaging process and not those who ate the food eventually.

Based on this risk assessment, the authorities remain very cautious regarding mass events and large scale travel because of the risk of an outbreak related to imported fresh food. As a consequence, school students and staff are asked to stay within the boundaries of their province for the last 14 days before going back on campus. This prevents families from taking trips for short holidays. Although parents are allowed to travel for business, with a clear priority on essential business, it may be impossible to ban all imports of fresh food.

These are some of the insights of the most knowledgeable China-based foreign analysts of the epidemic in China.

Our analytical innovation lies in the regularity and breadth of the data we collect, and we think our data on China has great value because the best way to fight this epidemic is to understand what happened / is happening in China, with appreciation for the success of its massive testing and zero-risk strategies, rather than cursing China for being the birthplace of the virus.

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