According to WHO, China's Sinopharm COVID vaccine has "not yet been evaluated in the context of circulation of widespread variants of concern".
So maybe they don't have a choice and that letting COVID run through whilst everyone could be effectively unvaccinated would quickly overwhelm their health care system and lead to mass death.
Xi very much cares about political stability and it would be pretty toxic if China has all of these troubles whilst the rest of the world has moved on.
China could have bought vaccines from other makers. Sinopharm wasn't very effective to begin with ( https://www.who.int/news-room/feature-stories/detail/the-sin... has it at 79% compared to the Pfizer and Moderna vaccines starting out in the mid 90% range).
Realizing that I am delving into speculation, this sounds more like the refinement of establishing a police state where one can use "someone you came in contact with tested positive for Covid" and shutting down large segments of a city and sending people to government quarantine camps than a desire for political stability.
So maybe they don't have a choice and that letting COVID run through whilst everyone could be effectively unvaccinated would quickly overwhelm their health care system and lead to mass death.
Xi very much cares about political stability and it would be pretty toxic if China has all of these troubles whilst the rest of the world has moved on.