To reach herd immunity, 65% of the of the population needs to have Sars-Cov-2 immunity. If the initial vaccine is 80% effective, 81.25% of the population needs to be injected, assuming no one is initially immune. However, 35% of Americans don’t want to take the injection for one reason or another. So, pay them, maybe $1,200? This would certainly be better than simply handing out another round of $1,200 checks.