New research: Introduction of vaccine passports increased vaccination uptake in lagging countries

Using data from April to September 2021 in six countries where certification was legally mandated (Denmark, Israel, Italy, France, Germany, Switzerland), the study used modelling to estimate what vaccine uptake would have been without Covid-19 certification in each of the six countries, based on vaccination uptake trends from 19 otherwise similar control countries without Covid-19 certification.

In the main analysis, authors estimated the number of additional doses per population attributable to the policy. As a secondary analysis, the authors examined the impact of the policy on reported infections.

In countries where vaccine coverage was previously low, introduction of Covid-19 certification was associated with a significant increase in the number of additional vaccine doses per million people —127,823 in France, 243,151 in Israel, 64,952 in Switzerland and 66,382 in Italy. In contrast, in Denmark and Germany, where there were higher average vaccination rates before certification was introduced, there was no significant increase in vaccination.

Compared to the control countries, daily Covid-19 case numbers decreased after implementation in France, Germany, Italy, Switzerland, but increased in Israel and Denmark. Many countries implemented certification as a response to rising cases, making it difficult to assess the effect of certification on reported infections.

Increases in vaccination were highest in people under 30 years old compared to older groups. The authors explored whether prioritisation of vaccine rollout among older groups and eligibility in younger age groups around the time of certification may have influenced the results, but found that the effect could not be fully explained by age-based eligibility criteria.

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