The COVID-19 pandemic illustrated that intolerance of uncertainty (IU) can hinder problem-solving and lead to avoidance of ambiguous situations. Furthermore, people tend to lack confidencein decisions made in ambiguous contexts. We wanted to investigate the impact of IU on intentionsto get vaccinated, to vaccinate one’s children, and to recommend the vaccine in situations withvarying degrees of perceived uncertainty. We first conducted a pretest to select six scenarios withdifferent levels of perceived uncertainty. In the core study, 485 participants answered for each of thesix scenarios whether they would get vaccinated, vaccinate their children (or imagine doing so, forindividuals without children), and whether they would recommend the vaccine. They also completedthe IUS-12 (Intolerance of Uncertainty scale) and the VAX (Vaccination Attitudes Examination).Results showed that perceived uncertainty did not influence our measures, but the IUS-12 and VAXpredicted the difference in score between the most and least uncertain scenarios. An indirect effect ofthe IUS-12 on decision confidence through the VAX was found, but with no direct effect. We concludethat, even if future studies should refine these results, Public Policies should be more focused onfactors such as IU and attitudes toward vaccination.