When asked about vaccine safety, Republicans and Democrats express vaccine-hesitant beliefs at roughly the same rate. But when asked about government mandates, Republicans are much more likely to take the vaccine-hesitant stance, according to Allan McCoy, a sociology professor at State University of New York. In a 2018 study published in Critical Public Health, McCoy compared two Pew Center surveys on vaccine beliefs. He found that the more ideologically extreme a respondent was — regardless of whether they’re on the left or right — the more likely they were to think that vaccines are unsafe. But when asked if vaccines should be compulsory or left up to parents, respondents who identified as “very conservative” were 136 percent more likely than “moderates” to think it should be a parent’s choice, while those who were “liberal” and “very liberal” were 44 percent and 13 percent less likely to think so, respectively. Democrats and Republicans are almost equally likely to hold anti-vaccine beliefs, but Republicans in particular also tend to be against vaccine mandates.

But if vaccine hesitancy before the pandemic was relatively bipartisan, vaccine hesitancy around the COVID-19 vaccine has been anything but. Polls and vaccination rates have shown Republicans are less likely to be vaccinated, and more likely to say they don’t plan to get the shot than Democrats. Shana Kushner Gadarian, a political science professor at Syracuse University, and her colleagues have been conducting a panel survey of 3,000 Americans for the past 18 months. Gadarian told me there has been a partisan split on all health behaviors (not only the vaccine but also mask wearing, hand washing, visiting one’s doctor) throughout the pandemic.