Shanghai, the most populous city in China, has been under lockdown for the past month as it pursues a 'zero-COVID' strategy for eradicating the virus.
The country's approach aims to cut transmission as soon as possible, using stringent measures such as short and targeted shutdowns and quick testing schemes where cases are found.
Despite this, cases of the highly transmissible Omicron variant have risen in Shanghai and other cities over the past month.
While there have been reports of hospitals in Shanghai being overwhelmed by cases, deaths from COVID-19 still remain very low.
Since the outbreak of cases in March this year, at least 190 people have died with COVID-19 in the city of 25 million people.
As a proportion of its population, this figure is well below the current COVID death rate in the UK and US.
China had not reported a single death for a year until the recent outbreak in March. Scientists have attributed its success to its zero-tolerance policy for infections and high vaccination rates.
According to our analysis, five in six people in China were fully vaccinated by mid-April. This compares to just four in six people in the United States.
So what's holding back China from lifting restrictions if its vaccination rates are high?
The answer partly lies in who China has vaccinated.
Unlike the UK where the elderly and vulnerable have been prioritised for vaccinations, China's vaccine uptake has been higher among young people instead.
Health authorities in Beijing said last week only 57% of people over 60 had been fully vaccinated with three jabs. In comparison, 80% of over 60s have had three doses in the UK.
China's zero-COVID policy reduced the urgency to vaccinate all of the country's most vulnerable people, according to Dr Zhengming Chen, professor of epidemiology at the University of Oxford. As a result, an estimated 50 million still remain at risk.
"It's a victim of its own success," said Dr Chen.
"There are still very large numbers of clinically vulnerable and elderly people who are not fully vaccinated, which can lead to a rise in hospitalisation and mortality.
"That's why they're still reluctant to open up to live with [the] virus at this stage."
Experts also point toward the effectiveness of China's homegrown vaccines, which are much less effective than foreign-produced jabs
Chinese authorities last year recommended the Sinovac jab be boosted with a more effective mRNA vaccine, such as the Pfizer/BioNTech jab. That came after real-world data from Chile showed increased mortality rates against the Delta variant, even among those fully vaccinated by the Chinese vaccine.
Politics of lockdown
China's zero-COVID strategy was introduced after the initial outbreak in Wuhan in 2020.
However, due to its success at keeping COVID-19 cases and deaths low for over two years, Chinese authorities have not changed their policy despite the virus mutating to a more transmissible variant.
Transitioning to a policy of looser restrictions where cases and deaths will inevitably rise will always be "challenging" for any government, says Martin Hibberd, professor of emerging infectious diseases at the London School of Hygiene & Tropical Medicine.
"When you step [away] from that kind of complete control to allow the number of cases to increase, that's difficult, especially politically."
"The policies that worked well for the original variant are going to be much more difficult to implement for the Omicron because it's so much more transmissible."
"That requires a decision from the government to make that change in message, and I don't think they've quite done that yet."
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