They may live in rural areas, hence not feel the need to get vaccinated, but do they show up for work in person, where they can catch Covid, or do they work remotely?
Do they shop for food and other goods and services in person, where they could catch covid, or do they order everything online and get it delivered, with no contact with the delivery person, which limits their chance of catching covid?
Do they ever have the local plumber or roofer or whatever show up and do work around the house?
Do they ever hang out at the local bar or restaurant or store, where they can interact with others and catch covid?
Living in a rural area is no guarantee of safety or immunity.
Do they go to motorcycle rallies and party before going back to their rural homestead?