Using behavioral theory to understand partisan differences in COVID-19 vaccination and booster intentions.

In 2020, the Food and Drug Administration granted emergency use authorization for two COVID-19 vaccines. Two years later, the Centers for Disease Control and Prevention estimated that more than 250 million individuals had received at least one dose of the vaccine. Despite the large numbers of individuals vaccinated against COVID-19, partisan differences surrounding the COVID-19 vaccine emerged, creating a potential challenge for health communications aimed at increasing vaccine uptake.