Let's say it works, who makes it? Single dose to get herd immunity just in the US, we'd need 230 million doses (assuming 70% for herd immunity). If it's a two dose vaccine, that's over 500 million. We don't have ANYWHERE near that manufacturing capacity. We make approximately enough vaccine for the birth cohort of 4 million, and about 4 million more for seniors. Finally, we manufacture 160 million doses of flu vaccine each year. And that's just in the USA. Where's the additional capacity coming from? China?
Discovering the vaccine may be the easiest part of this equation.