Reminders of existing vaccine mandates increase support for a COVID-19 vaccine mandate: Evidence from a survey experiment

BACKGROUND: Governments are trying various strategies to boost COVID-19 vaccination rates, including vaccine mandates. Popular support for such mandates, however, is in flux in many countries, including the United States. The objective of this study is to evaluate if the wording of public health messages could increase popular support for COVID-19 vaccine mandates. METHODS: We conducted a survey experiment on a sample of 573 registered voters in South Dakota, United States. Participants in the control group (n = 271) read a short message about mandatory COVID-19 vaccination. Respondents in the treatment group (n = 278) read the same message but they were reminded that a variety of vaccine mandates for measles, mumps, rubella, and polio have long been required. Afterwards, both groups were asked about their support for COVID-19 vaccine mandate. RESULTS: A multivariate ordinary least squares regression analysis revealed that the experimental treatment had a positive and statistically significant impact on support for mandatory COVID-19 vaccination (p < 0.001). We also found that COVID-19 vaccination status, religious identity, and political affiliation have a statistically significant effect. CONCLUSIONS: Our findings suggest that a simple intervention—reminding the public of the existing vaccine mandates—increases support for COVID-19 vaccine mandate. Public health authorities who seek to boost COVID-19 vaccination rates could utilize this approach.