Do Conspiracy Theories Shape or Rationalize Vaccination Hesitancy Over Time?

Conspiracy beliefs are associated with vaccination hesitancy, which is commonly interpreted as evidence that conspiracy theories contribute to a worldview that damages public health. An alternative, and often ignored, explanation for this relationship is that people may rationalize their existing vaccination hesitancy through conspiracy theories. In two panel studies conducted at multiple time points during the vaccination campaign of 2021, we tested the temporal relationships between COVID-19 conspiracy beliefs and vaccination intentions. Study 1 (three waves in a Dutch sample) provided evidence for temporal effects of conspiracy beliefs on vaccination hesitancy and of vaccination hesitancy on conspiracy beliefs. Study 2 (two waves in a U.S. sample), however, only supported an effect of vaccination hesitancy on conspiracy beliefs over time. Although these findings provide some support for the idea that conspiracy beliefs shape increased vaccination hesitancy, they more consistently support the alternative idea that vaccination hesitancy shapes increased conspiracy beliefs.