Mar 30, 2020 08:56 PM

Opinion: China Should Disclose Asymptomatic Covid-19 Cases

Photo: Ding Gang/Caixin
Photo: Ding Gang/Caixin

China has recently reported multiple asymptomatic Covid-19 infections, including both imported and domestic cases. So far, Beijing has neither included these individuals in its confirmed case counts, nor disclosed statistics for this category to the public. Thus, the scale of asymptomatic infections in the country remains unknown.

Meanwhile, asymptomatic individuals have been identified as the source of confirmed Covid-19 cases many times. Health authorities should release statistics on asymptomatic individuals and sufficiently investigate the situation in order to educate the public and prevent the disease from coming back.

On Sunday, the Henan Provincial Health Commission reported it had confirmed a case of Covid-19 contracted by somebody who was in contact with an asymptomatic individual in the city of Pingdingshan. This case has attracted public interest in asymptomatic cases — those who are infected by the novel coronavirus, but show no symptoms such as fever or respiratory difficulties.

Scientists have not yet reached a conclusion on transmissibility of the virus between asymptomatic individuals and others who later show symptoms. However, recent research shows there are no substantial differences in the viral load carried by these two types of individuals.

China’s top epidemiologist Zhong Nanshan has stated that asymptomatic individuals were close contacts with confirmed cases who had large amounts of the Covid-19 virus in their upper respiratory tracts and could be infectious, according to a report from national broadcaster CCTV on Sunday.

But he didn’t believe that at this stage there would be large numbers of asymptomatic cases in China. If there were, he argued, the total number of confirmed cases would rise — not the other way around — because asymptomatic individuals could infect others. However, he also clarified that “I don’t have any data or research to show exactly how many asymptomatic individuals there are.”

The absence of public statistics on asymptomatic cases could bring concern, or even panic, to the realm of public opinion, creating an environment for rumors to spread. There are also concerns that not disclosing asymptomatic cases could be a convenient way for local governments to withhold information.

Many experts have called for a complete investigation into asymptomatic cases in Wuhan. Hu Zhibing, an epidemiologist at Nanjing Medical University, said Wuhan has the capability and should actively investigate asymptomatic cases to avoid a possible comeback of the disease after the lockdown ends.

Unlike many other countries, China doesn’t count asymptomatic cases when it reports confirmed infection numbers. The total numbers from its reports are divided into separate categories including asymptomatic cases, but they are not announced to the public.

This is different from standards set by the WHO, which say that any laboratory-confirmed infection should be considered a confirmed case, regardless of whether there are clinical signs and symptoms.

To be in line with international standards, asymptomatic cases should be included with statistics for confirmed cases, or be listed as a separate item and publicly announced. This will help China and the international community integrate and work together by agreeing on disclosure standards for epidemic research and judgment — one of the foundations for collaboration. China shouldn’t be absent from the table as other countries put asymptomatic cases into their total confirmed figures.

Disclosing the scale of asymptomatic cases can also assist supervision of related work. It will put an end to the deceptive practice of putting confirmed or suspected cases into the asymptomatic group in the pursuit of attaining “zero” figures for new cases.

Let’s take the example of the disclosure of two asymptomatic cases from Henan’s Pingdingshan that were confirmed using nucleic acid tests on Wednesday. In a widely circulated investigative report, one of the cases was self-described as “having a little cold” before the diagnosis. Are Covid-19 and a cold related? How was the diagnosis made with this asymptomatic case? Did it involve “technically deceptive reporting?” The public will only become suspicious when cases are disclosed late or not made public. Putting numbers out for everyone to see and allowing for public oversight will reduce the possibility of a second outbreak.

Three days ago, Premier Li Keqiang clearly stated the importance of paying attention to asymptomatic cases in a meeting with policymakers. On March 23, Li also publicly said that while most places have reported no new cases for several consecutive days, we must still remember to provide timely, honest and accurate statistics and not engage in deception by excluding cases simply in the pursuit of “zero new infections.”

In truth, providing complete data during the outbreak will not only take pressure off local officials but will also be welcomed by the general public. Once the public actively discovers missing information, the relevant institutions will become passive players in the realm of public sentiment.

Active disclosure isn’t the same as “revealing your dirty laundry.” In fact, it’s a science-backed policy decision for controlling the outbreak. At the moment, the country has clear disclosure requirements for the outbreak, with a requirement for honest and accurate reporting. It is imperative that data on asymptomatic infections gets published as soon as possible to meet the premier’s requirements to seek the truth from facts and respond to social concerns in a timely and public way.

Contact translators Lu Zhenhua and Yang Ge ( and

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