MoH data is a bit sparse on detail but still mentions 300K+ doses of vaccine administered daily.
http://www.nhc.gov.cn/xcs/yqjzqk/list_gzbd.shtml
The economist has some aged grouped vaccination data from the end of March that actually shows pretty good vaccine coverage for the 60-79 age group. I couldn't find a source but the numbers are consistent with a prior press release.
https://www.economist.com/china/2022/04/02/why-so-many-elder...
Really? The data I've seen (googling and on social media) suggest that there is no change in the vaccination rate.