Vaccine passports are something that in theory would allow organizers to take in a larger audience more infection-proof.
The questionnaire refers to a certificate that shows a negative PCR test, evidence of antibodies or that you have taken two injections of vaccine.
A total of 1,063 people aged 18–79 were interviewed in Kantar Sifo's web panel during the period 26–29 August.
The web panel is nationally recruited based on random selections.