On Questions of COVID Mitigation Methods, South Dakotans are Sharply Polarized. (n.d.). South Dakota State University. Retrieved 8 October 2021, from https://www.sdstate.edu/news/2021/09/questions-covid-mitigation-methods-south-dakotans-are-sharply-polarized

Youyang Gu. (2021, June 30). South Dakota has a vaccination rate of 50% (1+ dose). Maine is at 66%. So is Maine better protected? Not quite. If you factor in immunity from natural infection, SD has a total population immunity of ~70%, while ME is at ~62%. I created a calculator: Https://t.co/j4tMI2zN2K [Tweet]. @youyanggu. https://twitter.com/youyanggu/status/1410264061900726283