Much of what happened next doesn't add up.
By late January, Wuhan's hospitals were already reportedly under severe strain. They offered 90,000 beds. Another 100,000 beds were activated in hotels and schools. Yet Beijing's figures reported only 33,000 Covid-19 cases.
By March 23, 42,600 doctors and healthcare workers had been rushed to Wuhan from other provinces to support the 90,000 already there. But Beijing reported only 50,000 cases.
And where there's smoke, there's fire.
Before Beijing's crackdown, China's bureaucracy had been conducting business as usual – analysing, assessing and reporting on everything about its citizenry. The researchers from Washington University and Ohio State University say they have tracked down this early government data and combined it with reports in state-controlled and social media.
Among this data was the activities of eight crematories in Wuhan. By January 25, these were inexplicably operating around the clock.
Based on such sources, the researchers argue the total number of infections and fatalities before February was at least 10 times that of the official figure announced by Beijing.
Rubbery figures
It took just weeks for Covid-19 to appear in 188 countries. In six months, the virus has infected more than seven million people worldwide and killed at least 400,000.
As the pandemic continues to swell, critical eyes are turning on Beijing's handling and reporting of the outbreak. The notorious information-management and censorship of the Communist state are being accused of delaying the international response to the crisis.
"China's Covid-19 statistics fall outside of recognised and accepted medical norms" the study finds.
But cracks are appearing in the great firewall of China.
The Wuhan City Health Commission had reported 27 cases of pneumonia of unknown origin in December before Beijing intervened. The study points to other official Chinese reports from this time, indicating anywhere between 266 and 45,100 unidentified cases.
"Chinese media raised concerns about infections and deaths beyond the official statistics; for example, when the director of a fever clinic complained that he could admit only five out of 80 potentially infected patients, which suggested a potential 16-fold difference between possible infected patients and confirmed diagnoses in Wuhan," the report finds.
Another potential cause of confusion is the role private clinics played, it says. State-controlled Chinese media at the time reported these services had been falling through "reporting gaps".
Such wildly varying stories have "led many to believe there may be serious gaps in our understanding of the outbreak based on what can be determined from this official government data," the report states.
Where there's smoke ...
The US researchers say they have identified an important clue in the reported activities of Wuhan's strictly regulated crematorium business.
Typically, these are restricted to operating just four hours each day. This is usually in the morning in keeping with Chinese funeral traditions.
But by January 25, the crematoriums were operating at six times their regulated rate.
They were burning 24 hours a day.
The report estimates the usual funeral figure for a city of nine million people would be about 136 a day. Escalating operations by up to six times enables about 816 daily cremations. With mobile crematories known to be in action, the peak daily figure could have been as high as 2100.
The study tracked the sale of funeral urns to verify the estimates. In the January-March period during which the crematoriums were operating at peak levels, some 36,000 had been distributed.
The report says it took 14 days before the drastic lockdown measures imposed upon Wuhan on January 23 began to take effect. By this time, it says the death toll was already likely in the tens of thousands.
"The estimates of cumulative deaths, based on both funeral urns distribution and continuous full capacity operation of cremation services up to March 23, 2020, give results around 36,000, more than 10 times of the official death toll of 2524," it reads.
Information wars
The study says that, based on its inferred data, China may have had anywhere between 305,000 and 1.27 million Covid-19 cases by February 7. The number of dead, it finds, was likely already about 6800 to 7200.
Official figures released by Beijing at this time reported only 13,600 infections and 545 dead.
"The magnitude of discrepancy between our estimates based on cremation related data and Chinese official figures in early February, the critical time for response to the Covid-19 pandemic, suggests the need to re-evaluate official statistics from China and consider all available and reasonable data sources for a better understanding of the Covid-19 pandemic," the study asserts.
A slew of unconfirmed evidence has since pointed to origins possibly as early as August. This has ranged from unconfirmed US spy-agency wiretap and intelligence reports to data analysis of population movements and purchasing patterns.
This study applies Covid-19 uncontrolled "doubling rate" to the newly inferred infected figures to come up with a potential October origin.
"If the doubling time 6.4 is close to the truth, there was significant under- and delayed reporting of the Covid-19 epidemic information by China in late January and early February, the critical time for the world to respond and prepare for the pandemic," the study finds.
"Given the serious implications of the Covid-19 pandemic, further investigations into this period in China needs to be carried out."
Discrepancies in Beijing's response to the Wuhan crisis and its publicly declared position have been raising suspicions for months. But the challenges of finding reliable data to test these claims remains significant.
"Readers are reminded of the assumptions that underlie our estimates, and they should, therefore, be taken as approximate," the study's authors warn.
"However, even if there were non-negligible reporting errors in these new data, the magnitude of the discrepancy between the results from their analysis and China's official figures suggests that the potential impact on the global efforts to control the pandemic is obvious."
