One report [55] described the use of counterfeit certificates for yellow fever. In December 2018, Nigeria and other countries introduced machine-readable yellow fever cards, but cards could still be obtained without evidence of vaccination. More outbreaks were predicted as people continue to carry fake vaccination certificates throughout Africa.
Search Results
The search of peer-reviewed databases identified 6292 citations; searches of pre-print databases identified a further 18 citations. Of these, 1133 were duplicates and were removed, with 5178 citations remaining. A search of the grey literature identified 25 additional citations. After title, abstract and full-text screening of all citations, 33 were judged to meet the eligibility criteria. Additionally, 1 article was identified through backward referencing (see Figure 1).
32 of the 33 studies used quantitative methods, with one study using qualitative (narrative) methods. Of the quantitative studies, the majority were cross-sectional surveys (n=30), with the remaining being experimental in design (n=3). Studies were conducted in a variety of countries: Germany (9), UK (10), US (3), Australia (2), Canada (1), Nigeria (1), Poland (1), Romania (1), Spain (1) and Switzerland (1). Three studies drew large samples from several countries (15, 19 and 11 respectively). Of the types of intervention that were the focus of studies, 2 concerned test-negative result for current infectiousness, 14 concerned test-positive for antibodies conferring natural immunity, and 17 concerned vaccination(s) conferring immunity. The majority of studies related to Covid-19 (31), with one concerning yellow fever, and one other concerning flu vaccinations.
Risk of Bias analysis
Using the MMAT, the mean average risk of bias score was 1.5 from a maximum of 5 (where a higher score means lower risk of bias). In many cases authors did not describe studies in sufficient detail for an evaluation to be made (see Supplementary Information: https://osf.io/357kt/?view_only=475cd0776a274e6bbc74f95e1eecd0e0 ). Based on the available information, 15 of the studies were rated as low quality, 14 as medium, and three as high.
Overview
We present a narrative analysis of the results on the impacts of certification in four areas: (1) public acceptability; (2) effects on uptake of tests and vaccination; (3) impact on behaviours that affect transmission and (4) crime. All results are summarized in Table 1.
Table 1: Study characteristics
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Author
(Date) Country of Study
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Study Design
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Participants
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Data collection period
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Disease
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Intervention
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Findings
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Adepoju, P.
(2019) Nigeria
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Narrative
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N/A
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N/A
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Yellow fever
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Vaccination certificate
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• Yellow fever is the only disease specified by WHO for which countries can require proof of vaccination from travellers. • The shortage of vaccines in Nigeria, combined with yellow fever epidemics, has led to the creation of a black market for counterfeit vaccination cards.
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Behavioural Insights Team (2020) UK
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Experiment
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4765
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13/11/2020 - 16/11/2020
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Covid-19
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Covid Test
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• A negative personal test result for COVID-19 decreases stated intention to comply with government guidance by 2ppt. Accompanying negative results with a certificate decreases stated intention to comply by a further 5ppt. • A negative test result decreases the proportion of participants saying they would not meet friends by 7ppt. Accompanying negative results with a certificate further decreases this by 6ppt.
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Betsch, C., et al (2020a) Germany
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Experiment
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993
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23/06/2020 - 24/06/2020
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Covid-19
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Mandatory vaccination
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• A hypothetical compulsory vaccination against Covid-19 had a negative effect on the willingness to undertake a voluntary vaccination against influenza. • Compulsory vaccination against Covid-19 (compared to voluntary vaccination) led to greater irritation, especially a) amongst participants who had an attitude that vaccinations should be voluntary and b) if the importance of high vaccination rates were not communicated. • Irritation then had a negative effect on willingness to accept the flu vaccination.
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Betsch, C., et al (2020b) Germany
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Survey
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1007
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05/05/2020 - 06/05/2020
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Covid-19
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Immunity certificate
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• 48.6% of respondents disagreed with the introduction of an “immunity card”, with around 25.6% agreeing. • 67% felt that those with immunity cards should have no privileges; 13% thought they should have freedom of movement; 8% fewer restrictions; 6% removal of the mask requirement. • Further analyses showed that the respondents would not intentionally get infected in order to receive an immunity pass (no data shown to confirm this)
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Betsch, C., et al (2020c) Germany
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Survey
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1014
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12/05/2020 - 13/05/2020
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Covid-19
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Immunity certificate
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• 45.1% of respondents disagreed with the introduction of an "immunity card", with 26.2% agreeing.
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Betsch, C., et al (2020d) Germany
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Survey
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972
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19/05/2020 - 20/05/2020
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Covid-19
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Immunity certificate
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• 45.2% of respondents disagreed with the introduction of an "immunity card".
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Betsch, C., et al (2020e) Germany
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Survey
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925
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25/05/2020 - 26/05/2020
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Covid-19
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Immunity certificate
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• 45.9% of respondents disagreed with the introduction of an "immunity card".
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Betsh, C. & Bohm, R. (2016) Germany
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Experiment
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297
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Not known
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Not specific
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Mandatory vaccination
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•Compulsory vaccination increased the level of anger among individuals with a negative vaccination attitude, whereas voluntary vaccination did not. This led to a decrease in vaccination uptake by 39% in the second voluntary vaccination (reactance). •Making selected vaccinations compulsory can have detrimental effects by decreasing the uptake of voluntary vaccinations
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Bricker, D
(6 Nov, 2020) Canada
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Survey
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1,000
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23/10/2020 - 26/10/2020
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Covid-19
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Mandatory vaccination
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•Support for mandatory vaccinations has fallen from 72% in July to 61% in October.
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COSMO
(2020) Germany
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Continuous surveys approx. each fortnight
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Varied: around 1000 each time.
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14/04/2020 - 15/12/2020
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Covid-19
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Mandatory vaccination
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• Vaccination intent has gone from 79% on 14/04/2020 to 49% on 15/12/2020. • Support for mandatory vaccination has gone from 73% on 14/04/2020 to 36% on 15/12/2020.
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Dennis, S. et al (2020) Australia
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Survey
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1169
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15/04/2020
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Covid-19
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Immunity certificate
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• Final support for immunity passports: 10.6% not at all, 49.9% slightly to moderately, 25.1% a lot to fully. • Likelihood of self-infection: 70.4% not at all, 21.7% slightly to moderately, 7.8% a lot to extremely.
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Feleszko, W. et al (2020) Poland
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Survey
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1066
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02/06/2020 - 09/06/2020
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Covid-19
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Vaccination certificate
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•Respondents indicating that they do not plan to vaccinate if the COVID-19 vaccine becomes available (N=301) were confronted with a list of eight different hypothetical reasons to vaccinate. When asked if any of the reasons would sway them to be in favor of being vaccinated, the majority (51%) answered that none of the presented reasons would change their decision. The list of presented reasons included both "High penalties for not vaccinating myself or my child (e.g. 5000 PLN equivalent ca. 1000€)" and "It is not possible to enter some countries without a vaccination certificate".
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Garret, P. et al (2020) Australia
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Survey
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449
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07/05/2020
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Covid-19
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Immunity certificate
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• Final support for immunity passports: 10.6% not at all, 49.9% slightly to moderately, 25.1% a lot to fully. • Likelihood of self-infection: 69.7% not at all, 22.6% slightly to moderately, 7.8% a lot to extremely.
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Graeber, D., et al (2020) Germany
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Survey
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851
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08/06/2020 - 04/07/2020
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Covid-19
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Mandatory vaccination
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• 70% of respondents would voluntarily be vaccinated against Covid-19. • 51% of interviewees are against and 49% in favour of mandatory vaccination. • The approval rate for mandatory vaccination is significantly higher among those who would get vaccinated voluntarily (59%) than those who would not be (27%). • Willingness to voluntarily be vaccinated is positively correlated with men, age, education, household income. • Mandatory vaccination is rejected with higher probability by women, but favoured by older people. Approval is negatively associated with neuroticism, and positively associated with subjective probability of contracting life-threatening Covid-19.
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Haney, C. & Laughlin, G.
(2020) US
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Survey
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1020
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Jun-20
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Covid-19
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Immunity certificate
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•22% of respondents would “probably” or “definitely” seek infection if earning immunity gave access to various opportunities: 14% to go to gatherings greater than 25 people, 13% to visit eldercare facilities, 12% to visit foreign countries, 10% to visit hospital patients, 11% to maintain or access employment at an eldercare facility. •Younger age was significantly positively associated with willingness to seek infection. •29% of gig workers reported they would seek self-infection to maintain or access employment in eldercare. •51% of respondents “strongly” or “somewhat” agree that eldercare facilities should be allowed to require immunity certificate from employees.
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Hearn, A. & Bull, T. (27 Nov, 2020)
UK
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Survey
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2,000
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Not known
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Covid-19
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Mandatory vaccination
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•45% of respondents think the Covid-19 vaccine should be compulsory, with 35% disagreeing entirely.
•Of those who did not want to be vaccinated, 19% would do so if they could go to the pub, 35% if they could go on holiday abroad, 28% if they could go to sporting, music or other events.
•71% of people think people arriving in the UK for holiday or business should have a certificate confirming vaccination, 70% think UK residents leaving the country should have a certificate saying they've been vaccinated.
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IATA
(August, 2020) 11 countries
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Survey
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4700 recent air travellers
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Aug-20
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Covid-19
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Covid test
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•88% were willing to undergo a COVID test as part of the travel process, 84% thought it should be required of all travelers.
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IPSOS Essentials (2020) 15 countries
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Survey
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14,500
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27/08/2020 - 30/08/2020
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Covid-19
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Mandatory vaccination
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• 39% of respondents in the UK “strongly support” mandatory vaccination; 31% “somewhat support” them. • Support for mandatory vaccinations is generally strongest in countries with the greatest health impact (Brazil, Mexico, India)
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IRES - Romanian Institute for Evaluation and Strategy
(2020) Romania
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Survey (Computer Assisted Telephone Interviewing)
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1027
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13/05/2020 - 14/05/2020
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Covid-19
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Immunity certificate
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• Over 4 out of 10 Romanians would be willing to be vaccinated against COVID - 19 once there was an approved vaccine, but 33% say they would not be vaccinated in any form. • 6 out of 10 Romanians would be willing to be tested in exchange for receiving an "immunity passport".
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Largent, E.A. et al. (2020) USA
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Survey
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2730
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14/09/2020 - 27/09/2020
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Covid-19
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Mandatory vaccination
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• 40.9% of respondents found state mandates for adults acceptable, and 44.9% unacceptable. • Slightly more respondents found employer-enforced employee mandates acceptable (47.7% acceptable to 38.1% unacceptable) • Individuals likely to get a COVID-19 vaccine accepted mandates at higher rates than those unlikely to do so (65% vs 17.3% for state-mandated, 72.5% for 22.9% for employer-mandated). • Acceptance of mandate was also positively associated with non-Black respondents and those with a bachelor's degree. No gender differences observed.
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Lazarus et al. (2020) 19 countries
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Survey
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13,426 (768 UK)
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16/06/2020 - 20/06/2020
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Covid-19
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Mandatory vaccination
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• There is a discrepancy between reported acceptance of a COVID-19 vaccine and acceptance if vaccination was mandated by one’s employer: all respondents, regardless of nationality, reported that they would be less likely to accept a COVID-19 vaccine if it were mandated by employers.
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Lewandowsky, S. (2020) Spain
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Survey
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1,500
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27/04/2020 - 02/05/2020
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Covid-19
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Immunity certificate
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• Final support for immunity passports: 17.3% not at all, 60.7% slightly to moderately, 22.1% a lot to fully. • Likelihood of self-infection: 65.6% not at all, 27.3% slightly to moderately, 2.9% a lot to extremely.
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Lewandowsky, S., et al.
(2020) UK
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Survey
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1500
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16/04/2020
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Covid-19
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Immunity certificate
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• The majority of respondents did not object to the idea of immunity passports, with over 60% of respondents supporting the idea to varying extents. • Over 60% of respondents wanted an immunity passport for themselves. • Around 20% of respondents considered immunity passports to be unfair and opposed them completely. • 79% of respondents would not consider at all deliberate self-infection to obtain an immunity passport, around 21% considered doing so to varying degrees. • Increased age, greater perceived risk of the disease, greater trust in government were positively associated with acceptance of immunity passports whereas gender had no effect.
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Lorenz-Spreen, P. et al.
(2020) Germany
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Survey
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1,109
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17/04/2020 - 22/04/2020
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Covid-19
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Immunity certificate
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Attitudes towards Immunity passports in Germany: Awaiting precise data
Available from: https://ai_society.mpib.dev/tracking-app/wave2.html#Immunity_Passports
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Nehme, M., et al. (2020). Switzerland
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Survey
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1425
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27/05/2020 - 27/06/2020
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Covid-19
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Immunity certificate
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• 60% of participants reported that immunity certificates should be offered to the general population. • The contexts where certificates would be perceived as most useful were taking a plane (73%) and entering a country (72%); fewer participants agreed with them being useful for participating in large gatherings (55%) or the right to work (32%). • 55% of participants thought a vaccination should be mandatory and 49% thought a vaccination certificate should be mandatory. • 68% felt there was a potential risk of discrimination. • 28.6% felt there was a risk of deliberate infection to acquire immunity.
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Qualtrics
(Sept 2020) USA
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Survey
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1,074
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21/09/2020 - 24/09/2020
|
Covid-19
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Mandatory vaccination
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• Requirements that would make respondents "a little more likely" or "a lot more likely" to vaccinate: • To visit a hospital or nursing home: 70% • Travel to another state without quarantining: 70% • Flying: 68% • Going into office to work: 60% • Large gatherings: 59% • Large religious gatherings: 55% • Attend school in person: 51%
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Redfield & Wilton Strategies
(2020)
UK
|
Survey
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1,500
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16/05/2020
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Covid-19
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Immunity certificate
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•69% of respondents would support a policy of immunity certificates, with 16% against. •30% of respondents believe an immunity certification policy would implicitly reward those who did not follow social-distancing measures. •19% of respondents would consider deliberately catching coronavirus in response to a policy of immune certification, whilst 71% would not; 9% were unsure.
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Savanta:Comres (2020) UK
|
Survey
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2,090
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20/11/2020 - 22/11/2020
|
Covid-19
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Mandatory vaccination
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• Where it is voluntary to receive the vaccine 67% are likely to get it and 23% unlikely. When it is mandatory without legal penalty, less are actually likely to get it (65% to 24%). A legal penalty does not make much difference (65% to 25%).
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Waller, J., et al. (2020). UK
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Survey
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1204
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28/04/2020 - 01/05/2020
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Covid-19
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Immunity certificate
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• Participants did not perceive any difference in risk between the terms Passport, Certificate, or Test for an antibody test. • When using the term Immunity, 19.1% of participants perceived no risk of catching coronavirus compared to 9.8% for the term Antibody. • Perceiving no risk of infection was associated with an intention to wash hands less frequently, but there was no significant associated with intended avoidance of physical contact.
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YouGov
(2 Dec, 2020) UK
|
Survey
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5351
|
02/12/2020
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Covid-19
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Mandatory vaccination
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•37% of respondents supported government making it legally compulsory for all people in Britain to be vaccinated against Covid-19, with 44% opposing.
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YouGov
(24 Nov, 2020) UK
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Survey
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4,311
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24/11/2020
|
Covid-19
|
Vaccination certificate
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•72% of people support all airlines instituting a policy of only allowing passengers who can provide proof that they have been vaccinated (42% strongly support, 30% somewhat support). 18% of people disagree and 11% don't know. • Support appears to be correlated with age. No relationship with social grade.
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YouGov
(8 Dec, 2020) UK
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Survey
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5396
|
08/12/2020
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Covid-19
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Vaccination certificate
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•Those who should have been vaccination should not be subject to any more coronavirus restrictions: 22% •Everyone should be subject to the same coronavirus restrictions until most people have been vaccinated: 66%
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YouGov/Sky
(2 Dec, 2020) UK
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Survey
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1706
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02/12/2020 - 03/12/2020
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Covid-19
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Vaccination certificate
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•50% of respondents would continue to follow coronavirus rules and restrictions just as strictly after having a vaccination; 29% less strictly, 11% not at all. •Opinions of whether it would be "acceptable" to only allow people who have had vaccination to: •Travel by plane: 54% acceptable, 29% not acceptable, 17% unsure •Go to the cinema: 44% acceptable, 37 not acceptable, 20% unsure •Go to a restaurant: 39% acceptable, 43% not acceptable, 19% unsure •Travel on public transport: 36% acceptable, 46% not acceptable, 18% unsure
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Various terms were used to refer to health certification documents, including ‘certificates’, ‘passes’ and ‘passports’, referring to infection, virus, antibodies, immunity and vaccination. The terms used in this section are infection certification (based on test-negative results for infection, whether lateral flow test or qPCR) and immunity certification (based on either a test-positive result for antibodies or a completed COVID-19 vaccination).
Public acceptability
Ten studies of public opinion regarding health certification were found. Some asked about access to particular activities while others simply asked about the use of health certification in principle. In addition, eight studies examined attitudes towards mandatory vaccination.
Infection Certification: One study surveyed plane passengers (n= 4700) from 11 countries in August 2020. 84% were in favour of infection certification for air travel [24].
Immunity Certification: from antibody testing: Four surveys carried out in Germany in May 2020 (ns between 925 and 1014) found that between 45% and 49% disagreed with the introduction of an “immunity pass”, with around 26% agreeing [25, 26, 27, 28]. Two surveys carried out in Australia in April and May 2020 (ns = 1169 and 449) found that ~11% did not support immunity ‘passports’ or ‘certificates’ at all but ~75% supported them slightly to fully [29, 30].
Other studies asked about attitudes to immunity certificates for different purposes. Across five studies (n ~1000 to ~1700) conducted in four countries between April and December 2020, a majority of participants (54% to 73%) were in favour of the use of immunity certificates, particularly in the context of international travel [31, 32, 33, 34, 35]; a minority (15-20%) strongly opposed their use. One study (n ~1000) conducted in Germany in May 2020 found the opposite, with more people opposed to than supporting “immunity cards” [36]. A UK survey carried out in December 2020 (n = 1706) reported that while 44% of respondents found vaccination certification acceptable for going to the cinema, this fell to 39% for going to a restaurant [37]. In another UK survey carried out in December 2020 (n = 5396), 22% of respondents said that those who have been vaccinated should not be subject to any more coronavirus restrictions while 68% disagreed [38]. The percentage in favour of immunity certificates for use for the right to work was much lower than in the case of travel. Across three studies in three countries carried out in April – September (n ranging from 1000 to 1500) support ranged from 20% to 51% [31, 33, 39].
There was little information in most studies on how any of the attitudes described above varied across social groups. In the UK, one study found that acceptance increased with age, greater trust in government, and higher perceived risk of COVID-19 [31].
Immunity Certification: from vaccination Only one study of attitudes towards vaccination certificates specifically (n = 4311) was retrieved, conducted in the UK in November 2020, which assessed attitudes towards their use on international flights. 72% supported their use (42% strongly) and 11% strongly opposed them [40]. Support was strongest in older age groups, and unrelated to gender or socioeconomic status.
Mandatory vaccination The terms ‘mandatory’ and ‘compulsory’ vaccination were used in studies to refer to a general requirement by governments for all citizens to be vaccinated, but with the means by which this could be achieved usually left unspecified. A UK survey published in November 2020 (n = 2000) found that 45% of respondents thought the Covid-19 vaccine should be mandatory for everyone, with 35% disagreed entirely [41]. Of those who did not want to be vaccinated, 19% said they would do so if they could go to the pub, 35% if they could go on holiday abroad, and 28% if they could go to sporting, music or other events. A UK survey carried out in December 2020 (n = 5351) also found that 37% supported compulsory vaccination [37]. A survey carried out in Germany in June and July 2020 (n = 851) found that 51% of respondents were against and 49% in favour of mandatory vaccination. The approval rate was significantly higher among those who would get vaccinated voluntarily (59%) than those who would not be (27%) [42]. An American survey carried out in September 2020 (n = 2730) found that acceptance of mandatory vaccination was positively associated with non-Black respondents and those with a bachelor's degree [43]. An international survey (15 countries) carried out in August found that support for mandatory vaccinations was generally strongest in Brazil, Mexico, and India [44]. A survey in Canada (n = 1000) found that support for mandatory vaccinations fell from 72% in July to 61% in October 2020 [45]. Similarly, a survey in Germany (n = 1169) found that support for mandatory vaccination declined from 73% in April 2020 to 36% in December of the same year [46].
Uptake of tests and vaccination
Few studies addressed the possible impact of certification on uptake of vaccines or tests. A number suggested that intention to get vaccinated would vary with both the activity enabled by this and the source recommending vaccination.
Infection Certification: No studies were found.
Immunity Certification: from antibody testing An online experiment carried out in the UK in April 2020 (n=1204) found that 85% would definitely (56%) or probably (29%) have an antibody test if offered [47].
Immunity Certification: from vaccination One US study (n ~1000) conducted in September 2020 assessed ‘vaccine rules that would resonate’ [48]. The activities requiring vaccination certification for which most people said they would get a COVID-19 vaccination were: visit a hospital or nursing home (likely uptake rate of 70%), travel to another state (70%), air travel (68%), work (60%), attending large non-religious gatherings (59%), attending large religious gatherings (55%), and attending school (51%). However, a Polish study carried out in June 2020 (n = 1066) [49] found that of those who did not plan to get vaccinated, 51% were not swayed by any reasons. Indirect evidence that certification of vaccination for access to work could reduce uptake of vaccination is provided in a survey of 13,426 adults in 19 countries carried out in June 2020. A baseline of 71% reported that they would be very or somewhat likely to take a COVID-19 vaccine, compared with 61% if the vaccine was recommended by an employer [50]. However, an American survey carried out in September 2020 (n = 2730) found that slightly more respondents found employer-enforced employee mandates acceptable (47.7%) than unacceptable (38.1%) [43]. Those reporting higher levels of trust in information from government sources were more likely to accept a vaccine and take their employer’s advice to do so [50].
Mandatory vaccination: Two studies with experimental designs carried out in Germany (ns = 993 and 297) found that if a vaccination were to be presented as compulsory this led to anger (compared to voluntary vaccination) which then had a negative effect on willingness to accept a subsequent vaccine [36, 51]. A UK survey carried out in November 2020 (n = 2090) found that, for mandatory vaccination, the numbers saying they would or would not get a vaccination did not vary depending on legal penalty (65% to ~25% in each case) [52].
Impact on behaviours that reduce transmission
The evidence for possible behavioural outcomes of certification is summarised below first, amongst those with a certificate, and second, amongst those without a certificate.
Those with a certificate
Infection Certification An online experiment (n = 4765) conducted in November 2020 in a UK sample found that intentions to fully follow guidance were 61% for those receiving a negative test result but 56% for those receiving a certificate alongside their negative test result [53]. For those not asked to imagine they had undergone testing, 63% reported fully following guidance.
Immunity Certification: from antibody testing Another UK online experiment (April 2020, n = 1204) assessed the impact of describing a positive test indicating presence of antibodies on risk perception and protective behaviours [47]. Using the term ‘immunity’ as opposed to ‘antibody’ increased the proportion who erroneously perceived they would have no risk of catching coronavirus in the future given an antibody-positive test result, from 9.8% to 19.1%. Perceiving no risk of infection with coronavirus given an antibody-positive test result was associated with an intention to wash hands less frequently.
Immunity Certification: from vaccination. A UK survey carried out in December 2020 (n = 1706) found that 50% of respondents said they would continue to follow coronavirus rules and restrictions just as strictly after having a vaccination; 29% less strictly; and 11% not at all [37].
Those without a certificate
Having failed an immunity test The majority of participants in a Swiss survey said they expected that tests showing an absence of antibodies would encourage people to take more precautionary measures such as wearing of face coverings (76%) and respect for social distance measures (87%) [33].
Having not applied for a test Six studies in four different countries conducted between April and June 2020 (n > 1000 each) reported between 19% [39, 54] and 31% [29, 30, 31, 32] of participants saying that they would likely expose themselves to infection in order to get a certificate. More students compared to other groups reported that they might deliberately infect themselves (58%) [31]. In another study, those who were younger and those who worked in the “gig” economy (29%) were more likely than others to report that they would seek self-infection to maintain or access employment [39]. However, a survey study carried out in Germany in May (n = 1007) found that no respondents reported they would intentionally get infected in order to receive an ‘immunity pass’ (though no data was shown to confirm this) [25]. A further study (in Switzerland) examined expectations of others’ behaviour and found that 28.6% thought that others might self-infect (respondents were not asked how they themselves might respond) [33].
Crime
One report [55] described the use of counterfeit certificates for yellow fever. In December 2018, Nigeria and other countries introduced machine-readable yellow fever cards, but cards could still be obtained without evidence of vaccination. More outbreaks were predicted as people continue to carry fake vaccination certificates throughout Africa.