The virus, vaccination, and voting

Vaccination rates have a statistically significant downward effect on the Covid-19 death rate across US counties, as of August 12, 2021. Controlling for poverty rates, age, and temperature lowers the magnitude of the estimate a little. Using the Biden-Trump vote in the 2020 election as an instrument for vaccination rates raises the magnitude of the estimate. Presumably it corrects for a positive effect of observed local Covid deaths on the decision to get vaccinated. Overall, the estimated beneficial effect holds up and has risen over time.