Their two main COVID vaccines aren't terrible as far as I can tell but they're not great. Against classic Wuhan and I'm not sure about pre-Omicron variants. Which we've got some data saying is as bad as the previous ones to the totally immunologicaly naive (although per another paper 30% tested had general protection against all coronaviruses due to their adaptive immune systems targeting some of their most basic functionality and the four strains that were endemic prior to COVID).
There's theoretical reasons to believe they might hold up better than solely spike protein focused vaccines; a greater problem could be low uptake, especially among the elderly (the PRC doesn't have a great record overall with vaccines). See this recent HN discussion: https://news.ycombinator.com/item?id=34053879#34054893 which covers other issues on the ground.
An even bigger problem is, aside from the measures people are themselves taking, Xi has in effect done an all or nothing approach, first Zero COVID then when that became unsustainable and regime threatening "let it rip."
