As Covid barrels through China, scientists around the world are searching for clues about an outbreak with sprawling consequences — for the health of hundreds of millions of Chinese people, the global economy and the future of the pandemic.
But in the absence of credible information from the Chinese government, it is a big scientific guessing game to determine the size and severity of the surge in the world’s most populous country.
In Hong Kong, one team of researchers pored over passenger data from five Beijing subway lines to determine the potential spread. In Seattle, a group of modelers tried in vain to reverse-engineer an unverified government leak detailing case numbers from Chinese health officials. In Britain, scientists are coming up with their own efficacy estimates of Chinese vaccines.
Any personal anecdote or social media report from China — scarce medicines, overrun hospitals, overflowing crematories — is possible fodder for researchers’ models.
They are all attempting to understand the same things: How quickly is the virus spreading in the country? How many people are dying? Could China be the source of a new and dangerous variant?
As scientists sift through varied sources of shaky information, they are bracing for potentially catastrophic outcomes. Barring new precautionary steps, some worst-case estimates suggest that Covid could kill as many people in China in the next four months as it has Americans during the entire three-year pandemic.
Without satisfying answers, some countries are putting limits on Chinese travelers, albeit based in part on unfounded fears or political motivations. The United States, Italy and Japan have said they will require a negative Covid test for those coming from China, citing concerns that the surge in cases in China could produce new, more threatening variants. On Friday, France and Britain announced similar measures.
While researchers and virologists said the new measures would most likely do little, if anything, to blunt the spread, the policies reflect the limited visibility into the outbreak. Scientists’ models generally point to an explosive spread and a high death rate, given how many people in China have little to no immunity to Omicron sub-variants. But even their estimates are all over the place.
But scientists are skeptical of such a scenario in China’s current outbreak.
Variants similar to those that China has reported were largely outcompeted months ago in the United States by more contagious or more elusive Omicron sub-variants. After Italy mandated testing for travellers from China, it said the first cases it sequenced were all caused by an Omicron variant already present in Italy. European Union health officials said on Thursday that screening travellers from China was unjustified.
“We’ve had a huge number of infections internationally,” said James Wood, an infectious disease expert at the University of New South Wales in Sydney, estimating that most people globally had caught the virus. “That’s a lot more infections than have occurred in China alone.”