Immunity passports have the potential to allow large-scale international traveling to
resume. However, they can only become an effective tool if they are widely supported by the general
public. We carry out a double blind randomized online experiment with a sample of N = 4000
Americans to study (i) whether two nudges can increase the level of support for a COVID pass for
international traveling, (ii) the relationship between the effects of the nudges, and (iii) if these nudges
have a negative spillover on the intention to get vaccinated. We find that both nudges increase the
support for the COVID pass and that their impact is stronger when they are used together. Moreover,
we find that the two nudges do not negatively affect intentions to get vaccinated. Our findings have
important implications for policymakers and for the nascent literature on the interaction between
multiple nudges.