We compared the impact of epidemiological evidence and anecdotal evidence on changing vaccination attitudes amongst alternative medical students. Ninety-seven students were randomized to either an evidence-based lecture on the benefits of the polio vaccine on population health or a presentation from a visibly affected victim of polio. We compared change in responses to a survey measuring vaccination attitudes between the two groups. The follow-up rate was 73%. There was no statistically significant difference between the two groups in change in response to any of the survey questions. In a post hoc analysis we found that 25% of students were less likely to recommend the vaccine after being provided with evidence supporting vaccination. These findings suggest that confronting deeply held beliefs regarding vaccination may paradoxically strengthen these belief systems.