"Outside of Wuhan, no evidence was found of any significant increase in overall mortality, suggesting the success of the rapid control of the spread of SARS-CoV-2 in addition to appropriate maintenance of healthcare services during the nationwide lockdown."
In this thread I will use travel data to show that the lockdown was too late for this to have been possible.
I will further show that this study uses distorted graphs making the lockdown look like it occurred earlier than it really did.
Liu J, Zhang L, Yan Y, Zhou Y, Yin P, Qi J et al.
Excess mortality in Wuhan city and other parts of China during the three months of the covid-19 outbreak: findings from nationwide mortality registries
BMJ 2021; 372 :n415
doi:10.1136/bmj.n415
Here I've created a composite of the previous image with a WHO image produced from the same data set.
I used GIMP to add daily/weekly tics to the x axis and vertical red lines showing the false and true dates of the lockdown.
The left dotted vertical line is claimed to fall on January 23rd, but actually falls on January 17th.
The vertical red line on the right shows the correct lockdown date of January 23rd.
With the correct placement of the vertical line it's possible to see that excess mortality had already risen substantially before the lockdown was implemented.
Both publications use January 1st 2020 as day 1 of week 1, which I only note because the convention in both China and the US is for day 1 of week 1 to always fall on the Sunday of the week containing January 1st, which usually means day 1 falls during the last week of December of the previous year.
The discrepancy in the Y axis is likely due to this:
"we used the 2019 population in each DSP area to calculate weekly or quarterly mortality rates in 2020 (see supplementary table 3), which were then multiplied by 52 or 4, respectively, to yield annual mortality rates to facilitate comparisons. "
WHO image is Fig. 12. A from the "WHO-convened global study of origins of SARS-CoV-2: China Part"
The Wuhan lockdown occurred on January 23rd 2020, which happened to be the peak travel day for "the worlds largest annual migration" - the Lunar New Year.
Data from Baidu shows that the peak travel day is 2 days before the lunar new year.
There's a lot to unpack in these images, but the dates on the x axis of the selected graph are for the year 2024, and the years 2023 and 2019 are lined up by the lunar calendar rather than by date.
The peak travel day is the same all three years.
In 2024 the Lunar New Year fell on February 10th and the peak travel day was February 8th.
In 2020 the Lunar New Year fell on January 25th, and the expected peak travel day would have been on January 23rd.
https://www.nationalgeographic.com/history/article/lunar-new-year
Data from flightradar24 shows normal flight patterns until the lockdown.
Wuhan Tianhe International Airport can be seen in orange at the bottom.
The following visualizations were produced from cell phone data and published in the New York Times.
All of these travelers were from Wuhan.
"About 7 million people left in January, before travel was restricted."
Worth noting: more travelers went to Rome than Milan, and more travelers went to Los Angeles and San Francisco than to New York City.
https://www.nytimes.com/interactive/2020/03/22/world/coronavirus-spread.html
The 7 million travelers estimated by the New York Times is comparable to the 5 million estimated by the mayor of Wuhan.
https://www.pbs.org/newshour/health/where-did-they-go-millions-left-city-before-quarantine
"At least 300,000 people escaped on the eve of the lockdown"
https://web.archive.org/web/20240518170223/https://news.ltn.com.tw/news/world/breakingnews/3048974
To put this all together:
All cause mortality in Wuhan was well above normal by the time the lockdown was implemented.
Given that deaths lag infections, and given that only a small fraction of infections lead to death, the outbreak would have already been totally out of control by then.
The lockdown was implemented on the peak travel day of the worlds largest annual migration, and there was no travel slow down leading up to it.
An estimated 7 million people left the city in the weeks leading up to the lockdown, including 300,000 people on the eve of the lockdown.
Given this data, it is simply implausible that the lockdown meaningfully prevented overall mortality from increasing in Hubei province outside Wuhan or the rest of China.
Fig 1
Trends in weekly observed (dashed orange lines) versus predicted (blue solid lines) mortality rates for selected major diseases between 1 January and 31 March 2020 in China across different Disease Surveillance Point areas.
First vertical dotted line indicates the time when lockdown was implemented in Wuhan.
Cursor is pointing to the part of this image I'll be examining more closely.