Using Ipsos’ KnowledgePanel, the Tufts University Research Group on Equity in Health, Wealth, and Civic Engagement surveyed representative samples of Americans in 2020 and 2021. Among many other questions, we asked whether authorities should be able to mandate vaccination. Most respondents said no both times. Support declined from 42.6% to 34.5% from 2020-2021. Biden supporters were more favorable than non-voters, who were more favorable than Trump supporters. However, both Biden and Trump voters moved against mandatory vaccinations. Possibly, Trump supporters have become less likely to favor vaccination mandates now that the federal government is led by a Democrat, but that wouldn’t explain the decline among Biden supporters.
I report these results without a strong value-judgment. I think I would support mandates (with appropriate exemptions), but that's just an opinion. I don't have expertise or fixed views.
Some caveats: In 2020, we asked about vaccinations in general. In 2021, we asked about the COVID-19 vaccines. In 2020, we asked whether people would vote in the next November election--and if so, for whom. In 2021, we asked whether and how they did vote in the prior election. Too few people admitted they didn't vote; our turnout estimate is inflated by over-reporting.