One notion about how we get back to “normal” is that we will achieve herd immunity — the proportion of the general population with immunity that would block the ability of the virus to thrive and spread.

The odds say that’s not very likely. Firstly, there is no certainty that immunity lasts. Like the flu, having COVID-19 probably does not mean you won’t get it again. But the second problem is the percentage of immune people required: it’s estimated to be 40 to 80%. To reach 60% the number of deaths would be between two and three million in the US alone. The Washington Post simulations below will help you grasp the problem.