The very first coronavirus case in China can be traced back to November 17.
According to government data seen by the South China Morning Post, a 55-year-old from the Hubei province could have been the first person to have contracted COVID-19.
However, the scientists stressed that the 55-year-old was not "patient zero", who scientists expect will help them to trace the source of the virus, generally thought to have jumped to humans from bats.
Chinese authorities have so far identified at least 266 people who were infected with the deadly disease in 2019, all of whom came under medical surveillance at some point.
Some of the cases were likely backdated after health authorities had tested specimens taken from suspected patients.
Interviews between the SCMP and "whistleblowers" from the medical community suggest that Chinese doctors only realised they were dealing with a new disease in late December.
Scientists have been trying to map the pattern of COVID-19's early transmission since an epidemic was reported in Wuhan, two months before the outbreak became a global health crisis – and now, a pandemic.
More than 125,000 people have since been affected across more than 100 countries, health officials saying that the virus was proving "extremely difficult to track".
Understanding how the disease has spread – and determining how undetected and undocumented cases contributed to its transmission – will greatly improve scientists' grasp of how big a threat COVID-19 poses.
"It seems that the virus can pass from person to person without symptoms, making it extremely difficult to track, regardless of what health authorities do," specialist in cellular microbiology at England's University of Reading, Dr Simon Clarke said.
The Chinese government information showed that from November 17 onwards, between one and five new cases were reported each day.
Less than one month later, on December 15, the total number of infections stood at 27.
Five days later, the total number had reached 60.
On December 27, a doctor from Hubei Provincial Hospital of Integrated Chinese and Western Medicine, Zhang Jixian, told China's health authorities that the disease was caused by a new coronavirus. By then, more than 180 people had been infected, though it's likely doctors weren't aware of all of them at the time.
While the records have not been released to the public, they provide valuable clues about how the disease spread in its early days and the speed of its transmission.
Of the first nine cases to be reported in November – four men and five women – none has been confirmed as being "patient zero". All were aged between 39 and 79, but it's unknown how many were residents of Wuhan, the capital of Hubei and the epicentre of the outbreak.
It's possible that there were reported cases dating back even earlier than November.
The first confirmed case was previously thought to be on December 8, according to information on the World Health Organisation's (WHO) website.