Most scientists believe China’s decision to end its zero-COVID policy was long overdue. But now they have a new worry: that the country is collecting and sharing far too little data about the rough transition to a new coexistence with the virus.
China abruptly dropped virtually all controls a month ago, after protests, a sagging economy, and the extreme transmissibility of the virus’ latest variants made clinging to zero COVID untenable. Now, “SARS-CoV-2 has an open goal in front of it: a population with very low levels of standing immunity,” says evolutionary biologist Edward Holmes of the University of Sydney. But how the epidemic is unfolding is a mystery because the country has practically stopped collecting basic epidemiological data.
Models that predicted a massive wave of infection and death if China ended zero COVID appear to have been correct. Press reports and social media posts have shown intensive care units stretched beyond capacity, with crowds of patients in wheelchairs and on gurneys in hallways. Doctors and nurses are reportedly working while sick. Crematoriums are overwhelmed. But China’s official COVID-19 death toll is widely considered laughably low. And some scientists worry a genomic monitoring plan unveiled last month doesn’t have the power to detect new SARS-CoV-2 variants arising as the virus works its way through one-fifth of the world population.
Earlier in the pandemic China’s daily counts of COVID-19 cases and deaths, based partly on its exhaustive testing programs, were generally believed to be accurate. Now, they are anyone’s guess. Patients with mild symptoms are not encouraged to get tested, let alone those who are asymptomatic. People testing positive at home are not asked to report their results.
The China Center for Disease Control and Prevention (China CDC) put the number of confirmed cases the last week of December 2022 at more than 35,000—a fraction of the official number in the United States. But leaked notes from an internal meeting suggest a very different reality: The agency was told that almost 250 million people in China—roughly 18% of the population—may have caught COVID-19 in the first 20 days of December. Some experts said the number is implausibly large, but Yanzhong Huang, a global health specialist at the Council on Foreign Relations, a U.S. think tank, says it’s “not unreasonable,” given credible reports that 80% of Beijing residents have been infected by now.
As to the death toll, China’s reporting had long been inconsistent, Huang says, with some regions reporting all fatalities in which SARS-CoV-2 was a factor, as most countries do, and others excluding people who died from other conditions, such as heart attacks, even if they had COVID-19. In early December, China’s government decided the narrower definition should be used nationwide.
Even then, the official count is astonishingly low: just eight deaths for the entire last week of December, which is “not matching media reports and what is being seen on social media,” says Louise Blair, who tracks China’s COVID-19 outbreak for Airfinity, a London-based health analytics firm that estimates about 9000 people were dying of COVID-19–related causes every day in late December. Also missing are data on case fatality rates, the average number of new infections stemming from each case, and hospital and intensive care admissions. “These are critical data” that would help health authorities get a handle on the surge and further the world’s understanding of the pandemic, says Xi Chen, a public health scientist at the Yale School of Public Health.
A major worry is that the wave will breed a new and even more troublesome SARS-CoV-2 variant. “It’s possible that something might be emerging, because there is such a big population in China,” says George Gao, who in July 2022 stepped down as head of China CDC but is now helping track circulating variants. But, he told Science, “There are no novel mutants—yet.” At a 20 December press briefing, Xu Wenbo, head of the National Institute for Viral Disease Control and Prevention, explained that the BA.5.2 and BF.7 Omicron subvariants, which are now causing most infections globally, are also dominant in China. BQ.1 and XBB, which have recently been spreading in Europe and North America, have turned up in limited numbers in several provinces.
Experts are split on whether China is looking closely enough. Three designated sentinel hospitals in different cities in each of China’s 31 provinces, municipalities, and regions are supposed to sequence and analyze samples from 15 outpatients, 10 severe cases, and all deaths every week. “I’m afraid [that] sample size is too small,” Chen says. A stronger plan would consider province size and population density, instead of picking three cities in each, and adopt other sampling approaches, says Elizaveta Semenova, an epidemiologist at the University of Oxford. Semenova is a co-author of a study of how well 189 countries have detected new variants, published in November 2022. It concluded that effective surveillance requires sequencing about 0.5% of cases, with a turnaround time of less than 21 days. China’s plan is unlikely to come close to that percentage.
But Gao and others say the program will pick up new variants in a timely way. If the surveillance plan gets up to speed, it will sequence 2000 to 3000 genomes per week, a level that “should be able to detect [new variants] and their transmission trends,” says Leo Poon, a virologist at the University of Hong Kong who has helped track variants there. Poon notes that China is sharing data from the outbreak on GISAID, the world’s largest database of SARS-CoV-2 sequences.
In addition to China CDC, research groups at more than 30 hospitals and universities are also tracking SARS-CoV-2 variants, says a Chinese epidemiologist who asked not to be identified. These groups “will report immediately if a dangerous variant emerges,” the source says.
Still, the lack of reliable data is already undermining faith in China’s handling of the outbreak. A dozen countries, including the United States and France, have announced they will require pre- or postflight tests on air travelers from China. Huang says that is unlikely to keep new variants out. The goal should be to convince the Chinese to be more forthcoming about what’s happening on the ground—and for that, “quiet diplomacy may work better than travel restrictions,” he says.
Dennis Normile is a contributing correspondent in Shanghai, China.
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