The potential impact of vaccine passports on inclination to accept COVID-19 vaccinations in the United Kingdom: evidence from a large cross-sectional survey and modelling study
Authors: de Figueiredo Alexandre , Larson Heidi J. , Reicher Stephen 
Published: June 2021

BackgroundFour vaccines against the novel coronavirus 2019 disease (COVID-19) caused by the severe acute respiratory coronavirus 2 (SARS-CoV-2) have currently been approved for use in the United Kingdom. As of 30 April 2021, over 34 million adults have received at least one dose of a COVID-19 vaccine. The UK Government is considering the introduction of vaccine passports for domestic use and to facilitate international travel for UK residents. Although vaccine incentivisation has been cited as a motivating factor for vaccine passports, it is currently unclear whether vaccine passports are likely to increase inclination to accept a COVID-19 vaccine.MethodsWe conducted a large-scale national survey in the UK of 17,611 adults between 9 and 27 April 2021. Bayesian multilevel regression and poststratification is used to provide unbiased national-level estimates of the impact of the introduction of vaccine passports on inclination to accept COVID-19 vaccines among all respondents who have not yet had two vaccination doses. Multilevel regressions identify the differential impact of the likely impact of vaccine passports on uptake intent between socio-demographic groups. Gibbs sampling was used for Bayesian model inference, with 95% highest posterior density intervals used to capture uncertainty in all parameter estimates.FindingsWe find that the introduction of vaccine passports will likely lower inclination to accept a COVID-19 vaccine once baseline vaccination intent has been adjusted for. Notably, this decrease is larger if passports were required for domestic use rather than for facilitating international travel. The impact of passports while controlling for baseline vaccination intent differentially impacts individuals by socio-demographic status, with being male (OR 0·87, 0·76 to 0·99) and having degree qualifications (OR 0·84, 0·72 to 0·94) associated with a decreased inclination to vaccinate if passports were required for domestic use, while Christians (OR 1·23, 1·08 to 1·41) have an increased inclination over atheists or agnostics. There is a strong association between change in vaccination inclination if passports were introduced and baseline vaccination intent: stated change in vaccination inclination is thus lower among Black or Black British respondents (compared to Whites), younger age groups, and non-English speakers. We find notable sub-national trends, for example, that passports could increase inclination among students and Jewish respondents in London compared to those in full-time education or atheists or agnostics, respectively.InterpretationTo our knowledge, this is the first quantitative assessment of the potential impact of the introduction of vaccine passports on COVID-19 vaccine intention. Our findings should be interpreted in light of sub-national trends in current uptake rates across the UK, as our results suggest that vaccine passports may induce a lower vaccination inclination in socio-demographic groups that cluster geographically in large urban areas. Caution should therefore be exercised in introducing passports as they may result in less positive health-seeking behaviours for the COVID-19 vaccine (as well as other existing or future vaccinations) and may contribute to concentrated areas of low vaccinate uptake, which is an epidemic risk. We call for further evidence on the impact of vaccine certification on confidence in COVID-19 vaccines and in routine immunisations in wider global settings and, in particular, in countries with low overall trust in vaccinations or in authorities that administer or recommend vaccines.FundingThis survey was funded by the Merck Investigator Studies Program (MISP)Research in contextEvidence before this studyProof of vaccination has, to date, had limited use in public and private settings for the UK public, such as proof of yellow fever vaccination for international travel to limited destinations, or requirements of Hepatitis B vaccination in some medical roles. Although recent surveys have suggested that the majority of the British public support vaccine passports, we are not aware of any studies assessing the impact that proof of vaccination status for domestic use or for international travel may have on vaccination inclination and thus—perhaps more importantly—on epidemic spread.Added value of this studyWe conducted a large-scale survey of more than 17,000 members of the UK public to explore attitudes to vaccine passports for domestic and international use. Bayesian methods are used to compute nationally representative estimates of the impact of vaccine passports on change in inclination to accept COVID-19 vaccines and to establish the socio-demographic determinants of vaccination inclination. This study is, as far as we are aware, the first to assess the impact of vaccine passports on vaccination inclination in the UK.Implications of all the possible evidenceThis study provides novel insights into the potential impact of vaccine passports on COVID-19 vaccine intent in the UK. Although we find that vaccine passports receive popular support in the UK, there exists large variations in their appeal that stratify along socio-demographic lines. Most notably, younger age groups, Black and Black British ethnicities (compared to Whites), and non-English speakers are more likely to express a lower inclination to vaccinate if passports were introduced. Although these groups comprise a relatively small proportion of the UK population, there are crucial issues that these perceptions among these groups cause: notably, that these groups tend to have lower baseline vaccination intent and they cluster geographically. Therefore, since geographic clusters of low vaccination uptake can result in disproportionate increases in required vaccination levels for herd immunity in adjacent settings, we need to exercise extreme caution in public health interventions that may push these areas further away from vaccination. This is especially so if such an intervention will have little overall impact on the majority of the population outside these areas who are already quite willing to vaccinate. Overall, we find that the introduction of passports for either domestic or international use has a net negative impact on vaccination inclination, once we control for baseline vaccination intent. Our findings suggest that vaccination passports may not only yield damaging health outcomes for already marginalised communities: this may lead to further distrust in the government and public health systems and may have negative downstream consequences for other health-seeking behaviours, for example, routine immunisations.