The US messed up the pandemic under Trump but the reality is they are getting better. Their cases are falling. Their vaccination rate is the best in the world among large countries. And their technology is unsurpassed. Right now they are focusing on vaccinating their own people, but once that is complete, they will have an excellent infrastructure for export. They will use it against China if the mRNA vaccine has been tweaked to work with new variants successfully while China's vaccines become even less effective. China could even become dependent on the BioNTech vaccine licensed by Fosun and be forced to pay a lot of money just like they do now with semiconductors.
Some people think I discuss bleak situations for China because I am against China; this could not be further from the truth. Merely, I think it is more useful to discuss areas of potential weakness than strength. China has many strengths, and a strength is a strength; that is great, you accept it, and let it continue. But you focus on areas of weakness so you can improve. If my son brings home a B average report card, I don't say, "great you didn't get a C" I say "what can you change to get an A"? Given China's challenging international environment this is how it must think to survive.
I notice a distinct lack of critical thinking in this post. In addition to the comments already made, I would add the following:
Yes, the US will have infrastructure setup to produce and distribute vaccines inside the USA.
But these are currently mRNA vaccineswhich require temperatures of -20C and -80C for transport.
The amount of mRNA vaccine exports will be severely limited because the receiving countries don't have the infrastructure setup to store and distribute large quantities. And that is even before we consider the much higher cost of mRNA vaccines.