This video gives an idea of how China is managing its cities during the pandemic April 2022 (2 years after the start, but after the latest Omicron strain, when China locked down Shanghai again). Lots of images.
Lower immunity from natural infection - uniquely vulnerable. It was a source of national pride for Chinese that their case numbers had been so low, and they had so 'successfully' weathered the pandemic relative to other countries, although their strict lockdowns of cities caused economic and other problems (such as other health problems due to lack of diagnosis and treatment, access to medicine, etc, psychological problems from isolation, social issues from lack of socialization - it has been said (by Mill in the following terms) that the necessity of the mental wellbeing of people (on which all their other wellbeings depend) lies in freedoms) as well as extreme tracking and monitoring through electronic devices and registration. Some say the Chinese see the issue politically, as the Chinese system versus the West, so it may be less likely China would now permit opening the cities and having more infections, because of the images that would be shown to the world.