  Widespread uptake of vaccines is necessary to achieve herd immunity. However,
uptake rates have varied across U.S. states during the first six months of the
COVID-19 vaccination program. Misbeliefs may play an important role in vaccine
hesitancy, and there is a need to understand relationships between
misinformation, beliefs, behaviors, and health outcomes. Here we investigate
the extent to which COVID-19 vaccination rates and vaccine hesitancy are
associated with levels of online misinformation about vaccines. We also look
for evidence of directionality from online misinformation to vaccine hesitancy.
We find a negative relationship between misinformation and vaccination uptake
rates. Online misinformation is also correlated with vaccine hesitancy rates
taken from survey data. Associations between vaccine outcomes and
misinformation remain significant when accounting for political as well as
demographic and socioeconomic factors. While vaccine hesitancy is strongly
associated with Republican vote share, we observe that the effect of online
misinformation on hesitancy is strongest across Democratic rather than
Republican counties. Granger causality analysis shows evidence for a
directional relationship from online misinformation to vaccine hesitancy. Our
results support a need for interventions that address misbeliefs, allowing
individuals to make better-informed health decisions.
