Table 1 Eligibility criteria

The following articles were included:

Examined the general adult population rather than special/vulnerable populations

Included discussion of COVID-19 vaccine certificate characteristics (or synonyms such as immunity passports, green passes, proof of vaccination, etc.)

Included discussion of participants’ willingness to receive COVID-19 vaccines (acceptance, delay, ambivalence, hesitancy, etc.)

Evaluated the potential role of COVID-19 vaccine certificate on willingness to vaccinate

English language full text available

Primary research (e.g., observational, modeling, experimental, and qualitative studies)

The following articles were excluded:

No discussion of COVID-19 vaccine certificates (e.g., studies that broadly mentioned “vaccine mandates” without specifying vaccine certificates or synonyms)

No discussion of COVID-19 vaccine intention or uptake

Studies that generally described public opinions and attitudes on COVID-19 certificates and/or hesitancy but did not evaluate their interaction/association

No English language full text available

Review-type or non-empirical studies (e.g., commentaries, editorials, opinion letters, etc.)