Progressive underwrites their own health insurance. They do not purchase a plan from an outside provider. I guess you could call it a renewal, but they also have control over the pricing.
In certain ways, I'm not opposed to pricing behaviors like this. To me, it makes sense that someone who runs a half marathon once a year should pay less for health care than someone who eats fast food and doesn't exercise.
My concern with this particular policy is based on these issues:
1. Ignoring prior infection. We seem to be the only country in the world that does this. The overwhelming evidence at this point, especially with regards to the Delta variant, is that natural immunity is better. A vaccinated person is more likely to have a symptomatic infection, more likely to have a severe infection, and much more likely to have a death than someone with natural immunity experiencing a subsequent infection.
2. The BMI example I gave is by design. I bet the present value of future health care costs for an obese person is an order of magnitude greater than the present value of future costs of an unvaccinated person. You can even put aside the fact that an obese person is much more likely to have a severe Covid infection than a non-obese person. If the decision was really in the interests of the health and well being of the employees, and to get premiums inline with actual costs to the company, then the BMI metric would be an obvious choice.