Herd immunity isn't a thing for coronavirus yet.

Herd immunity only works when you have an effective vaccine/treatment, and it only helps the people who aren't eligible for that treatment. Given the coronavirus R0, you might achieve herd immunity when 75% of the population has been infected. Achieving herd immunity by letting the virus slowly spread until 0.5% or 1% of your people to die is a loss condition, that's millions of deaths. It's certainly better than letting it spread like wildfire and overwhelm hospitals so that 5% of your people die, no question there, but still not good.