If only there was an inter-national body that everyone contributes to and that does these things /s. Both parties here are at blame: China didn't fully cooperate with the WHO and the US recently kicked it out.
It's not obvious that international bodies are the answer. Health agencies the world over lied through their teeth to manipulate the public to take specific actions.
So if you believe that your lauded international bodies are immune to politics and the abuse of authority, then maybe it will work. The rest of us prefer international bodies to be forums and coordination points for the real authorities.