I don't just mean dollars. Getting everyone vaccinated is a huge national effort, nine to twelve months long, that we need almost everyone to participate in. Everyone has to trust the institution. So what happens if the first two vaccines were benign but also ineffective? How do you convince 300 million people that this time we've got it right?

It's worth noting the fastest ever vaccine development before this was 4 years; the early COVID vaccines were developed & authorized in 9 months and a large risk production ramp was started before authorization was granted.