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自然医学杂志nature3月28日刊文评论中国疫情防控政策

2022.3.29

自然医学杂志nature3月28日刊文评论中国疫情防控政策

Will Omicron finally overpower China’s COVID defences?

The country needs to control the virus until it has boosted vaccination rates in elderly people and reinforced the health-care system.

All eyes are on China as it attempts to quash its largest COVID-19 outbreaks since the early days of the pandemic. More than 62,000 people across all 31 of its provinces are infected, most of them with the fast-spreading BA.2 Omicron variant.

The outbreaks have plunged tens of millions of people into lockdown. President Xi Jinping announced earlier this month that China would stick to its ‘dynamic zero-COVID strategy’, which aims to stamp out infections and prevent the virus from spreading through communities. This policy now stands in contrast to a global trend towards easing restrictions and attempting to co-exist with the circulating virus.

China’s hard-line approach to eliminating COVID-19 seems to be softening. In his speech, Xi also flagged a more pragmatic strategy, asking that officials limit the economic impact of control measures. In practice, this means that people with asymptomatic cases of COVID-19 are being sent to dedicated isolation centres rather than hospitals, and are monitored for shorter periods than previously required. But some researchers are divided about whether the virus will spread out of control before the government has time to prepare.

Testing boost

“They’ve demonstrated time and time again that they can control outbreaks,” says epidemiologist Ben Cowling at the University of Hong Kong. The country successfully controlled the hyper-transmissible Omicron variant during the Beijing winter Olympics in February, despite predictions that large outbreaks would occur, he says. He anticipates that the aggressive testing efforts under way will see case numbers continue to rise over the next few days, but that numbers will fall back to zero after that.

If cases do drop, the government will probably spend the next year boosting the low vaccination rates in elderly people and establishing primary health-care infrastructure to ease pressure on hospitals, says economist Xi Chen at Yale University in New Haven, Connecticut, who studies China’s public-health system.

But others say that China needs to brace itself for a growing outbreak. New infections are edging towards 6,000 confirmed cases a day. “It’s growing quickly — I think it’s out of control now,” says Michael Osterholm, an infectious-diseases epidemiologist at the University of Minnesota in Minneapolis. Case numbers are unlikely to come back down to zero, he says, and trying to keep the virus suppressed would require such severe restrictions that “it surely will bring down their economy”.

If Omicron runs out of control, the effects could be devastating — and similar to the current outbreak in Hong Kong, where deaths have surged and hospitals are overwhelmed. An analysis by Airfinity, a life-sciences market analytics firm in London, suggests that more than one million people in mainland China could die during an Omicron wave, partly because only 50% of people over the age of 80 are fully vaccinated.

Lessons from Hong Kong

Recent experience in Hong Kong has highlighted the cost of low vaccination rates in older people. In early March, there were close to 900 cases of COVID-19 per 100,000 residents in Hong Kong, the highest level recorded anywhere in the world during the pandemic. Deaths have also surged to nearly 300 a day earlier this month. Experts blame low vaccination rates in elderly people for the region’s high mortality rate. Only about one-third of those aged over 80 years are fully vaccinated, and 90% of deaths have been in people who are not fully vaccinated.

Mainland China faces a similar predicament if the current outbreak is not controlled. China’s overall vaccination rate is higher than 85%. That has been achieved with the introduction of a digital vaccination-passport system — required for entry into many public buildings and workplaces — and a colour-coded ‘health code’ that indicates whether someone poses an infection risk. But Cowling says that older people are less likely to use facilities that require a vaccination passport and have been able to remain unvaccinated.

Fifty-two million people aged over 60 years are yet to be fully vaccinated. The most vulnerable — those aged over 80 years — are the least well vaccinated, with only 20% having received the primary vaccination course and booster shot. Work by Cowling and his colleagues that is yet to be peer reviewed indicates that the Sinovac vaccine, one of the two main vaccines used in China, is effective at reducing severe cases and deaths, but that the third shot is necessary to confer high levels of protection in those aged over 601.

Deaths from COVID-19 could be “much worse” than the 1 million estimated by Airfinity if Omicron spreads through the population, says Lu Jiahai, an infectious-diseases epidemiologist at Sun Yat-sen University in Guangzhou, China. The government is “taking responsibility for people’s lives, so will not change or relax the current prevention and control strategy”, he says.

Exit strategy

China’s large domestic economy has made a zero-COVID strategy more sustainable than it has been in places with smaller populations, such as New Zealand and Singapore. But it can’t last forever. The stock market index is falling, suggesting that China’s economy is suffering, and Cowling says that disruptive outbreaks will become more frequent as the virus circulates freely elsewhere.

Boosting vaccination rates in elderly people will be a priority, but many live in rural areas, so this will take time. Lu says that China will probably wait until the vaccination rate reaches 80% in that group before easing restrictions further.

Chen says that, at the moment, there are few family doctors in China, which means people rely on hospitals as their first port of call. He suspects that most COVID-19 restrictions will be in place for another year. This would allow the government to build up a fledgling family doctor network or dedicated isolation facilities to treat people with mild or asymptomatic COVID-19 and ease pressure on the hospital system. If the country isn’t prepared, re-opening could be “a disaster in terms of the health-care system”, says Chen.

Chinese authorities also need to prepare the public for what’s to come, says Chen. Many people have come to rely on the government’s willingness to use all means necessary to control the virus at the expense of the economy, he says.

doi: https://doi.org/10.1038/d41586-022-00884-z

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