Ministry of Foreign Affairs denied it yesterday. https://www.fmprc.gov.cn/eng/xwfw_665399/s2510_665401/202204/t20220415_10668556.html

I think the Russian side needs to elaborate. Did all cooperation stop or just a select few? It’s possible some scientists chose to not cooperate due to personal choice. I doubt a change in policy has occurred. If it did, we would also see a shift in rhetoric in Chinese media but nothing has changed.