I don't buy this. We all know how China and Russia (just like the US) work, they're all superpowers, and as such they all aim to supremacy. Russia blocked masks too, and China first reaction to the problem was silencing the doctor who isolated the pathogen, so really, we trust no one.
Any help we receive is appreciated of course, but it doesn't mean we're giving away our sovereignty just because they sent a cargo after fucking up like anyone else.