Sounds like the best laid plans to hold back covid in China are failing.

I don't think they've been effectively vaccinated. The "Sinovax" had mediocre effectiveness against the original wildtype, so it's probably not much good at all against the omicron variant. I've also read that (at least in Hong Kong) there is great vaccine hesitancy among the elderly who are also the most vulnerable.

https://www.reuters.com/business/healthcare-pharmaceuticals/chinas-sinovac-covid-19-vaccine-67-effective-preventing-symptomatic-infection-2021-04-16/

For comparison, Pfizer & Moderna were 95% effective against the original wildtype.