Can someone help me understand why they are having these waves? Is it because they won't use Western vaccines?
China is having the very large waves now because they locked down for so long. Thus they had a very small population with pre-existing exposure to the omicron strains. So when some BA.5 derived omicron strains starting getting into the Chinese population a couple of months ago they started taking off in the very large, very crowded (by international standards) cities.
Eventually enough people will be exposed to these new strains that their immune systems will be able to fight back and prevent reinfection and then we should see the shallower waves that are occurring in other countries now.
Compare what's happening now to China with their first Omicron wave to what happened to the US with their first Omicron wave: https://covid.cdc.gov/covid-data-tracker/#trends_weeklycases...
I've read that XBB.1.5 is about as different from BA.5 as BA.5 is from the original Wuhan strain. So even with this wave of infection China could get another wave of an XBB variant within a few months.