An apparent surge in traffic outside Wuhan hospitals from August 2019 may suggest the coronavirus hit the area earlier than reported, a study says.
Research finds rise in hospital car park usage and web searches for ‘diarrhoea’ and ‘cough’.
Coronavirus may have been present and spreading in Wuhan as early as August last year, according to a study that analysed satellite imagery of car parks outside major hospitals and search engine data.
The study, by researchers from Harvard Medical School, Boston University of Public Health and Boston children’s hospital, looked at images captured between January 2018 and April 2020 and found a “steep increase” in vehicle counts starting in August 2019 and peaking in December 2019. Between September and October, five of the six hospitals observed had their highest daily volume of cars in the period analysed.
China’s foreign ministry rejected the study, calling it “extremely absurd”.
According to the study, the increase in vehicle volume coincided with a rise in queries on the Chinese search engine Baidu for “cough” and “diarrhoea”, about three weeks before the confirmed rise in coronavirus cases in early 2020. The researchers noted that while queries for cough coincided with the influenza season, diarrhoea is a symptom specific to Covid-19.
“Increased hospital traffic and symptom search data in Wuhan preceded the documented start of the Sars-CoV-2 pandemic in December 2019,” the researchers said in a preprint, published by Harvard’s DASH repository.
“In August, we identify a unique increase in searches for diarrhoea which was neither seen in previous flu seasons or mirrored in the cough search data,” it said.
China’s foreign ministry spokeswoman Hua Chunying said on Tuesday in a regular press briefing that she had not seen the study but she rejected its conclusions.
“I think it is absurd, actually extremely absurd, to draw this kind of conclusion based on superficial observations such as traffic volume,” she said.
The origins of Covid-19, which was first detected in a cluster of cases associated with the Huanan seafood market in late December, has become an increasingly sensitive question as China fights off accusations that it should be blamed for the pandemic, which has killed more than 400,000 people around the world.