That's a possibility yes They refused foreign help https://www.foxnews.com/health/us-health-officials-on-coronavirus-outbreak "China spurned CDC offer to send team to help contain coronavirus: US Health Secretary" It doesn't prove anything in particular, but they still did, for a reason or another ... That being said, the problem I see with your scenario, is control By definition there's no control over a bioweapon, unless you have the cure, but even then it's not a done deal Best thing you can hope for is for the virus to mutate against its own interests, and then vanish