Amish community in Lancaster County reaches herd immunity from Covid-19

I’m not confident that that metric equates to what that doctor says it does. There’s no mention of how an infected person in a household was treated. I guess the assumption is that they were not quarantined from the rest of the household, but I’d like to see self-reports if nothing else.

The Amish are already a fairly isolated group, so (speculation) if most of their COVID cases are “people who have more dealings with Englishers,” which I would expect to be the case, then even if their incidence is lower than reported, their more external-facing folks might have a high-enough level of immunity to stop it spreading. It depends a lot on how people with COVID-like symptoms are treated within the community though, and this story and its links say nothing about that.