How Omicron variant of coronavirus led to bursting of China’s zero-Covid dykes

After three years of tough pandemic controls, China’s sudden U-turn on its zero-Covid policy last month has brought relief but also anxiety that the country is unprepared for the surge in cases. In the second of a five-part series on the policy change and its impact, Josephine Ma looks at the Omicron-induced collapse of the zero-Covid strategy.

Part of Guangzhou, the capital of southern China’s Guangdong province, made headlines around the world in mid-November when violent clashes erupted between angry migrant workers and police in hazmat suits.

Rare scenes of civil unrest in mainland China were repeated later that month when more protests against prolonged epidemic-control lockdowns broke out in cities including Urumqi, Beijing, Shanghai and Zhengzhou.

Edmund Huang, a property agent in Lujiang, in Guangzhou’s Haizhu district, said most people in the area had been infected with the coronavirus that causes Covid-19 even though it had been locked down for two months from around October 20, with all residents subjected to swab tests every one or two days.

“Over 90 per cent of the residents were infected,” he said. “People were infected even though they were locked in their homes. Everyone I know was infected.”

While China succeeded in containing Covid-19 during the first two years of the pandemic, the emergence of the highly transmissible Omicron variant of the coronavirus last year changed all that. The authorities tried hard to snuff out one Omicron outbreak after another, beginning in Tianjin in January last year, using extreme measures such as strict lockdowns and testing tens of millions of people.

The economic and social costs of those containment efforts continued to mount, while their effectiveness proved, at best, short-lived.

The mechanisms used to hold back Covid-19 – reliant on local government enforcement, public compliance and early identification of infections – eventually collapsed and Beijing abandoned the zero-Covid policy in early December.

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Experts said China had wrongly assumed it could contain such a transmissible virus and wasted almost an entire year that could have been used to prepare the population for the end of the zero-Covid policy by, for example, stepping up vaccination of the elderly.

Over the past three years, the coronavirus that causes Covid-19 – Sars-CoV-2 – has become more transmissible. According to an article in China CDC Weekly, which is published by the Chinese Centre for Disease Control and Prevention, the basic reproductive number (R0) of the Delta variant that caused an outbreak in Guangzhou in May and June 2021 was 3.2, meaning an infected person could infect around three others if there was no intervention.

But the transmissibility of Omicron was several times higher, with one published paper putting the R0 of the strain seen in Tianjin in January last year at 8.2. The R0 of the strain now circulating in China is between 10 and 18, according to state media.

Hong Kong, which successfully fended off four waves of infection for two years through social distancing, border controls and compulsory tests for selected buildings, could not hold off a fifth caused by an Omicron subvariant. A tsunami of infection hit the city from January to March last year, killing over 9,000 people, with scientists estimating at least half its population had been infected.

Kwok Kin-On, an assistant professor at Chinese University of Hong Kong’s school of public health, estimated that even with intervention measures, an infected person in that outbreak could infect six to 10 others.

But the central government in Beijing continued to trust that its own playbook could deal with an outbreak in Shanghai from March to May last year.

Shanghai had long been praised for taking a flexible approach to epidemic control. Instead of locking down whole districts, like many other cities, Shanghai locked down streets or subdistricts for compulsory PCR tests once infections were found. Infected residents and close contacts were quarantined, but large-scale social and economic disruptions were avoided.

But that approach did not work last March. According to a paper published by a group of Shanghai and Beijing scientists in the Lancet in September, the number of infections doubled every 3.2 days and even after a citywide lockdown was imposed on April 1, it took 13 days for the effective reproductive number (Rt) – the number of people a positive case could infect after interventions – to fall below one.

The paper attributed the failure of selective quarantine to the high transmissibility of the virus and its stealthy nature, as selective lockdowns were only effective if positive cases were identified before they had a chance to spread further. But during that wave in Shanghai, 85 per cent of cases were asymptomatic, the paper said.

Weak vaccination coverage made things worse.

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The paper said the inactivated vaccines used in Shanghai “provided very low protection against Omicron variant infection” – about 17 per cent after a booster dose – and even that level of protection quickly waned over time. That left the Shanghai population “particularly vulnerable”, it said.

The Shanghai outbreak was contained after two months of citywide lockdowns. But it was a pyrrhic victory at best, with shortages of daily necessities, mental health problems and deaths caused by the denial of access to healthcare facilities beginning to sow public distrust in the zero-Covid policy.

In the following months, Beijing tried to avoid repetitions of the humanitarian crisis caused by strict lockdown in Shanghai by shifting to a more sophisticated approach called dynamic zero-Covid, which was similar to the flexible approach Shanghai had tried at first. Local governments were ordered to act fast to outpace increasingly transmissible Omicron subvariants that were emerging.

Many local governments ended up resorting to protracted mass lockdowns despite repeated orders from Beijing to avoid such draconian measures, but they failed to stop the spread of the virus – and the large crowds that gathered for swab tests actually helped spread it.

“PCR testing sites have been regarded as the main places where the virus spread,” said Xi Chen, an associate professor of health policy and economics at Yale’s school of public health. “There were long queues, and people tested positive may bring viruses to others, followed by more infected people after a certain incubation period.”

In Yili prefecture in the Xinjiang Uygur autonomous region, some residents said almost everyone they knew had been infected, from healthcare workers to the grass-roots officials who imposed the lockdowns. However, the official tally showed only dozens of new cases a day.

In September, Yili residents took to the internet to air their grievances at acute food shortages during three months of lockdown. Residents of some other cities, including Lhasa, capital of the Tibet autonomous region, followed suit. A bus crash in Guiyang, Guizhou province, in September that killed at least 27 people who were being sent to compulsory quarantine sparked another online outcry across the country.

But local authorities were told to stick firmly to the zero-Covid policy to ensure a favourable environment for the Communist Party’s five-yearly national congress in October.

Sources said two camps of government advisers and officials had hoped to win the ear of Sun Chunlan, the vice-premier in charge of China’s response to the epidemic, late last year. Both used Hong Kong data to bolster their arguments.

Supporters of opening up, including renowned respiratory disease expert Zhong Nanshan, quoted Hong Kong statistics from after July last year that showed the number of severe cases was low due to the hybrid immunity achieved by increased vaccinations and previous infections.

Opponents cited data from the first three months of last year, when Hong Kong recorded the highest Covid-19 death rate in the world because of its large unvaccinated elderly population, to persuade the government to stick to the zero-Covid policy.

Local governments also complained to Beijing in the second half of last year about the strain on their resources due to the implementation of the zero-Covid policy.

Beijing issued a 20-point Covid-19 control guideline in November aimed at attaining two conflicting goals: stopping the community transmission of Covid-19 while minimising social disruption and enabling economic recovery.

The guidelines only added to widespread confusion, before a series of protests and the open defiance of quarantine orders saw the zero-Covid dykes burst.

The protests were triggered by a fire in a flat in Urumqi, the capital of Xinjiang, that killed 10 on November 24. It touched raw nerves around China because people feared they might not be able to escape if a fire broke out during lockdowns of their own buildings.

More public defiance of quarantine rules was also seen. Workers at a Foxconn factory that makes iPhones for Apple in Zhengzhou, the capital of Henan province, clashed with riot police during a lockdown in November, and a week later migrant workers ignored a lockdown in Haizhu to confront police on the streets.

Each act of public defiance led to concessions by the authorities. Foxconn workers were allowed to go home and received compensation after their protests, while Guangzhou and Chongqing lifted most Covid-19 restrictions on December 1.

Then, on December 7, the nation was shocked by the central government’s sudden abandonment of most of the restrictions that had been in place for almost three years.

“If you are talking about the timing, why is it so abrupt? I can think of nothing else but the social protest,” said Yanzhong Huang, a senior fellow for global health at the Council on Foreign Relations, a think tank based in New York.

He said that before the protests, the government had still been trying to double down on the implementation of its zero-Covid strategy, but afterwards “almost immediately, they started to use the terms ‘new tasks’, ‘new situations’, and stopped using the term ‘zero-Covid’”.

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Shan Wei, a senior research fellow at the National University of Singapore’s East Asian Institute, said many local governments were on the verge of collapse because of the zero-Covid policy.

“Some local governments may have run out of financial resources and could not bear to continue with mass tests, lockdowns and economic downturns and reduction in tax revenues,” he said. “For places that could no longer pay the price, they reacted to the central government signal of relaxation quickly because they could not bear it any more and they were on the verge of collapse.”

Medical scientists said the failure of the zero-Covid policy had been anticipated when the Omicron variant emerged at the beginning of last year.

Michael Osterholm, director of the Centre for Infectious Disease Research and Policy at the University of Minnesota, said it had been unrealistic to assume that Omicron could be contained.

“In their belief that they could control Omicron, they did very well with both Alpha and Delta variants, because they were not nearly as infectious,” he said. “It’d be like trying to put out a severe forest fire – it is difficult, but that could be done.

“Along comes Omicron, and it’s more like trying to stop the wind. You can’t – you can deflect it, but you can’t stop it. And they didn’t understand that. They thought that they could continue to use the lockdown zero-Covid policy approach and end the Omicron challenge, which just was not going to happen,” Osterholm said.

“Anybody could have seen this coming if they knew anything about this virus.”

While there was no “optimal time” to exit from zero-Covid, the U-turn in December put China in a particularly vulnerable position, experts said.

Chen said “an ideal time for China to start planning its phased reopening” would have been spring or summer last year, “because reopening takes time, virus transmissions are normally at bay in spring/summer, and population-level immunity built by mass vaccination” had not eroded much by then.

In mainland China, only 68.7 per cent of people aged over 60 had received three doses of a Covid-19 vaccine in November, official figures showed. For those aged 80 and over, the ratio was just 40.4 per cent – with at least 8 million in that age group completely unvaccinated.

But by May last year, just over 80 per cent of those over 60 had received two shots, meaning their immunity would have waned by November without a third jab.

“The fact that 8 million people over age 80 are not vaccinated at all – that’s like a can of gasoline waiting for a match to hit,” Osterholm said.

Additional reporting by William Zheng and Hayley Wong