Limitations
’ behavior
Our study has several limitations. First, the generalizability of results may be limited by our sample, which consisted of residents of Germany only. Second, due to the cross-sectional design, it remains unclear how the behavioral interventions may affect respondents’ behavior in the long term, including their future decisions on COVID-19 vaccination. Third, in keeping the questionnaire short to motivate respondents to complete it, we did not include questions on why respondents did or did not change their intentions and benefit-to-harm assessments, which is why we cannot shed light on the reasoning behind these changes. Fourth, we cannot exclude the likelihood that the vaccine-hesitant respondents who completed the survey were more motivated than the vaccine-hesitant population in general, which may again limit generalizability of results. Fifth, some respondents may have felt they needed to change their initial response after being exposed to either intervention; however, if such a demand effect had played a role it would have affected both groups. Sixth, we cannot rule out the existence of nonrespondent bias.