Beijing Olympics: Is China's zero-COVID strategy ready for challenges?

A staff member walks past a mural of the Olympic mascot Bing Dwen Dwen and Coca Cola-branded refrigerators at the Winter Olympic Village in Beijing, Dec. 24. AP-Yonhap

An all-out battle to eliminate hotspots has been waged for months. Each time the Delta variant of the coronavirus has escaped into the community in China, authorities have moved in hard and fast to cut the chain of transmission.

Communities have been shut down, mass testing rolled out and contacts traced. The measures add up to the country's zero-COVID strategy, an epidemiological full-court press that has been used time and again, from Guangzhou in the south to Inner Mongolia in the north.

In most cases, the outbreaks have been contained within a month but with Omicron, a more transmissible variant, sweeping the globe and the Beijing Winter Olympics just weeks away, all eyes are on whether this will continue to be the case.

So far China has reported nine COVID-19 cases caused by the Omicron variant, including two who were infected by a man returning from Canada. The National Health Commission has pledged tougher controls at the borders in land, sea and customs checkpoints, with measures including more frequent testing and extended quarantine if imported cases are found in quarantine.

Experts say China is at a greater risk of Omicron outbreaks and, although the zero-COVID approach might still work against the new variant, gaps need to be plugged and resources allocated to meet the greater challenge.

The arrival of the Winter Games means an easing in some of the border restrictions that have shielded the country from an onslaught of imported cases. Thousands of athletes and delegates will be able to enter China without quarantine if they have been fully inoculated. Booster doses are encouraged but not required.

However, studies indicate that primary immunization is not enough to protect people against the Omicron variant.

The Beijing municipal government said earlier this month that outbreaks at the Olympics were expected but they were confident of containing the cases within the "closed loops".

Nevertheless, limiting Omicron's spread will be a challenge, according to Professor Kwok Kin-on, a public health epidemiologist from the Chinese University of Hong Kong.

"China will have a certain level of opening to overseas athletes and coronaviruses might be introduced across the border and that can easily spread," Kwok said.

"The epidemic control at the border is excellent but there are still loopholes."

Professor Jin Dong-yan, a virologist from the University of Hong Kong, said recent outbreaks showed the border was not solid and China was at risk of big outbreaks.

Part of the problem was that cases were not detected until quite a late stage.

"The recent outbreaks in China, like Zhejiang province and in Inner Mongolia, were picked up when dozens of people were already infected and community outbreaks," Jin said, adding the source of the outbreaks could not be traced because the infections were already generations away.

He said later discovery of cases could mean months-long outbreaks, as was the situation in Taiwan in the middle of the year or has been the case in Vietnam since June.

"This might come again and again, posing a challenge to the zero-tolerance policy, but that's the reality," Jin said.

Workers deliver a cart loaded with equipment to a commercial plaza at the Winter Olympic Village in Beijing, Dec. 24. AP-Yonhap

As fast as health authorities have moved in the era of the Delta variant, Omicron could mean they will have to move even quicker.

Kwok said Omicron's high transmissibility resulted in cases doubling in about two to three days, posing a big problem for contact tracing.

"We have seen an instant response, including a partial lockdown, once an outbreak is identified in China, but when China faces the challenge of Omicron due to the short doubling time, contact tracing cannot be done easily," he said.

"That means [authorities] have to spend more resources, money to trace the cases.

"A lot of resources will have to be spent to make sure the epidemic can be kept well under control. It may take a longer time to halt the spread of the Omicron epidemic."

Cracks are also apparent in another bulwark against the coronavirus ― vaccination.

Roughly 85 percent of the country's population has received at least one dose of a vaccine, with jabs available to children as young as three years old.

But two doses of an inactivated vaccine, the variety mostly used in China's vaccination drive, can only offer a very weak, if not almost no, antibody response against the Omicron variant, according to various non-peer-reviewed studies.

For example, researchers at the University of Hong Kong and the Chinese University of Hong Kong said last week that in a joint study, three doses of the Sinovac vaccine did not produce enough protective antibodies to combat the Omicron variant infection.

And it is unclear how well the inactivated doses prevent severe illness or death, a job more for the cellular immunity induced by vaccines.

Jerome Kim, director general of the International Vaccine Institute, said the data so far was limited.

"Theoretically the use of the whole-virus vaccines [such as inactivated vaccines] may generate responses that might provide better cross protection against variants, but we don't know enough right now about which cellular responses are a correlate of protection," Kim said.

Kim said booster shots were already needed for broader control of the Delta variant and data suggested that Omicron, with an unprecedented amount of mutations on the coronavirus's spike protein ― the part that enables infection ― was even harder for existing vaccines to fend off.

Vaccination reduced the risk of infection, hospitalization and death, but there was not a lot of data on the effectiveness of the inactivated Sinopharm and Sinovac vaccines widely used in China, particularly during the Delta wave, he added.

A Chinese flag and a Beijing 2022 Winter Olympics flag flutter at the Beijing Winter Olympic Games village in Beijing on Dec. 24. AFP-Yonhap

Jin from the University of Hong Kong said antibody immunity from inactivated vaccines waned quickly and the doses were weak at inducing cellular immunity which is the human body's other defense against severe COVID-19, highlighting the need for rapid booster doses to increase levels of protective antibodies, preferably three months after the first two shots.

"There is some immune memory after vaccination ― the memory T cells and memory B cells. They probably can shorten the duration of the disease but they are not sufficiently fast," Jin said.

"Even if you have an immune memory, it comes in the second wave while you need the first wave to protect against infection or against severe disease. You need neutralizing antibodies there. Period."

Other vaccines could offer added protection. US drug developer Moderna reported in December that its Covid-19 mRNA vaccine boosters showed a significant increase in antibody levels against Omicron in preliminary lab trials. Pfizer announced similar results for the BioNTech mRNA vaccine.

Sinovac said three doses of its vaccine would offer protection against Omicron but the company released few details.

Kwok from Chinese University said the BioNTech vaccine could play a role in boosting the immunity in China.

Chinese pharmaceutical firm Fosun has deals to import and locally produce mRNA BioNTech vaccines, but it has been stuck in the regulatory approval process for months.

"We look at the facts that the performance of having the same inactivated vaccine as a booster is not as good as using the [BioNTech] vaccine," he said.

"The vaccine-acquired immunity level will go up substantially and Fosun can play a role in bringing the mRNA vaccines to China."

In terms of public health and social measures, there seems little more that the country can do. Widespread vaccination, citywide testing, frequent partial and citywide lockdowns - the latest one being in the northwestern city of Xian in Shaanxi province - have left little room for further tightening and wearied the public.

But a more dangerous variant such as Omicron might lift people out of pandemic fatigue and encourage them to continue to stick to those rules when they see necessary, according to John Drury, professor of social psychology at the University of Sussex.

Speaking in a personal capacity, Drury said the public's perception of threat had been one of the major predictors of adherence to mitigation measures since the start of the pandemic and, while some people expected that the public would become "fatigued" over time, a cross-national comparison last year found otherwise.

"For most countries, levels of adherence formed a U-shape. That is, while there was a decline in adherence as the pandemic declined, as infection rates rose again so did adherence," he said.

"The other factors that counteract weariness with the mitigation measures include the perceived effectiveness of the mitigation measures, group norms - what we think relevant others are doing - and sense of duty or solidarity.

"These factors are often linked. The fear we often feel is for others, the vulnerable people, our family, our community and not just ourselves. This promotes a sense of duty."