More than 4 per cent of 11 million residents in Wuhan, where COVID-19 was first detected, may have been infected with the virus, a new study by China’s top disease control agency shows.
The Chinese Centre of Disease Control and Prevention (CDC) published the results of a serological study of some 34,000 residents from Wuhan and other Chinese cities on its WeChat account earlier this week.
The post said the study was conducted one month after China successfully controlled the epidemic earlier this year, but did not specify which month.
The CDC said it found about 4.43 per cent of survey participants from Wuhan had COVID-19 antibodies in their blood.
Several mainstream international media outlets including the BBC and New York Times calculated that based on Wuhan’s population of 11.2 million people, nearly 500,000 people may have contracted COVID-19.
This figure would be 10 times the official count of 50,000 confirmed cases reported by the Wuhan Municipal Health Commission, not including asymptomatic cases.
The new findings come as an international team of experts will travel to Wuhan next week to commence a six-month World Health Organisation (WHO)-led probe into the origins of the COVID-19 pandemic.
Discrepancy ‘likely evidence of what did happen’
Terry Nolan, who is the Doherty Institute’s head of vaccine and immunisation research group in Melbourne, told the ABC this discrepancy was to be expected, as those counting cases during the early stages of Wuhan’s epidemic would have missed a lot of cases.
“In Wuhan in the beginning, no one knew how [the virus] was behaving,” Dr Nolan said.
“In the case-finding time of an outbreak, the last thing you worry about are asymptomatic cases, because you’re really focused on finding people who are sick, and who are sick enough to be able to transmit because they’re coughing and so forth.”
He said the 4.43 per cent antibody rate among those sampled in Wuhan was “where you’d expect it to be”, given that retrospective serological surveys often pick up antibodies in young people, who were less likely to have exhibited any symptoms during the initial outbreak.
To date, the CDC has not released the technical data from the study, which would show how the virus moved through different demographic groups, such as age, gender, or occupation.
Dr Nolan said it was also critical for people not to “jump to conclusions” about the numeric discrepancy signalling some greater conspiracy.
“The fundamental thing that underlies the suspicion [of China] is that the numbers are being manipulated for some greater political purpose. That’s something I’m very sceptical about,” Dr Nolan said.
“It’s frankly more likely to be evidence of what did happen at the time as their case finding was focused on symptomatic cases.”
When censorship and science collide
The CDC’s findings were first released on its official WeChat account earlier this week, though coverage of the report by state-owned media has been sparse.
While there is a report on Xinhua, another article on the findings on state-owned China Internet Information Centre – which also suggested that Wuhan could have recorded about 500,000 cases – was taken down on Wednesday night.
No other state-owned Chinese media has since reported the near-500,000 projection.
However, the ABC has identified some 160 posts discussing the report on Chinese social media platform Weibo.
He Jing, a prominent science editor in Shanghai, suggested on Weibo that the CDC’s report explained “why hospitals were overwhelmed” at the height of Wuhan’s outbreak.
It is unclear if there have been government-led attempts to censor, or downplay the findings of the CDC report in local media.
However, China’s censorship in general has led to criticism of Beijing’s handling of the pandemic in its early stages.
“I’m not naive about the way in which China operates as a country, but equally there are very fine Chinese scientists and epidemiologists, many of whom trained in Australia, and celebrate what we do internationally,” Dr Nolan said.
“It’s not them that’s the problem. It’s the controllers or the censors who are controlling the way in which data are appearing externally.”
At the height of Wuhan’s epidemic in February, Matthew Kavanagh, a specialist in global health and political science at Washington’s Georgetown University, wrote in The Lancet that Beijing’s top-down control of information hindered its capacity to get on top of the virus when it first emerged.
“Healthcare workers suspected an outbreak in early December 2019, but information with which the public might have taken preventive measures was suppressed, and communication channels that might have alerted senior officials to the growing threat were shut down,” Dr Kavanagh wrote.
“Police detained a clinician and seven other people posting reports on 2019-nCoV, threatening punishment for spreading so-called ‘rumours’.
“Social media was censored; a preliminary analysis of Weibo and WeChat published on China’s biggest online platform showed outbreak discussions were nearly non-existent through much of January 2020, until the Chinese government changed its official stance on January 20, 2020.”
While China appears to have COVID-19 numbers under control, it has continued to punish those who first blew the whistle about the virus, including a citizen journalist who first reported on the Wuhan outbreak and was handed a four-year jail term this week.