Coronavirus started circulating in China in October 2019, study claims

The first case of a human infected with SARS-CoV-2, the virus which causes Covid-19, may have occurred in China‘s Hubei province as early as October 7, 2019.

Only in mid-December, two months later, were the first cases officially described in Wuhan at the now notorious Huanan wet market. 

Fresh analysis of the virus’ spread and its ‘molecular clock’ revealed it was most likely already established in Wuhan by this point and had been circulating in Hubei at low levels in early-November 2019, and possibly as early as mid-October. 

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The first case of a human infected with SARS-CoV-2, the virus which causes Covid-19, may have occurred in China’s Hubei province as early as October 7, 2019 

But due to the novel symptoms of Covid-19 and an initially small number of infections, it was hard to identify the pathogen.  

As a result, the virus only came to the attention of the authorities when a cluster of mysterious symptoms linked to the Huanan Seafood Market were seen in December. 

This led to the now-discredited theory that the wet market, where a wide variety of animals are sold both alive and dead, was where the pandemic originated. 

Dr Jonathan Pekar from the University of California San Diego conducted a mathematical study to determine when and where it actually emerged.

‘In our primary analysis, we assume that November 17 [thick dotted line] represents the first documented case of Covid-19,’ the researchers write in their study, published in Science . They conducted further analysis under this assumption

Researchers believe the November 17 date [dashed line] was the first infection of the SARS-CoV-2 strain which went on to spread around the world. But a weaker version likely existed beforehand and it is this which first jumped from animals too humans. They believe this trans-species infection could have occurred as early as October 7 (start of pink slope) 

His team analysed 583 early virus samples from Hubei to find their latest common ancestor from which they all descended. They found they dated back to around December 9.

But reports of an unusual pneumonia-like condition were being reported in Chinese media before this date.

As a result of this, the researchers say the only logical explanation is that the first form of the virus which jumped from an animal into a human was a weak strain which quickly went extinct. 

But before it fizzled out, the researchers speculate it mutated to become more potent and this variant then spread throughout Wuhan and later the world. 

‘In our primary analysis, we assume that November 17 represents the first documented case of Covid-19,’ the researchers write in their study, published in Science. 

They conducted further analysis under this assumption using a computer model.

When accounting for a lag in transmission, detection and symptoms developing, the first case of Covid-19 infection occurred in Hubei on or around November 4, 2019, the researchers calculate. 

However, this figure could be as early as October 7, the researchers add. 

The researchers struggled to pinpoint a geographical location for the viruses origin, but say if the initial strain — which was weaker than the Wuhan variant and all subsequent mutations — emerged in a rural location, it would have had to migrate to an urban location to survive. 

‘The lack of reports of Covid-19 elsewhere in China in November and early-December suggests Hubei province is the location where human-to-human transmission chains were established,’ the researchers write.   

The researchers add that their findings do not shed light on if the first case caught the virus directly from bats or via an intermediate host, but does ‘further distance’ the first case from the Huanan Seafood Wholesale Market.