Variables	Measures and Items	Assessment/Score
Vaccine Literacy functional skills	When reading or listening to information about future COVID-19 vaccines or current vaccines: Did you find words you didn’t know? Did you find that the texts were difficult to understand? Did you need much time to understand them? Did you or would you need someone to help you understand them?	Ordinal, 4 points Likert scale for frequency: Often (1), Sometimes (2), Rarely (3), Never (4)
Vaccine Literacy interactive/critical skills	When looking for information about future COVID-19 vaccines or current vaccines: 5.Have you consulted more than one source of information? 6.Did you find the information you were looking for? 7.Have you had the opportunity to use the information? 8.Did you discuss what you understood about vaccinations with your doctor or other people? 9.Did you consider whether the information collected was about your condition? 10.Have you considered the credibility of the sources? 11.Did you check whether the information was correct? 12.Did you find any useful information to make a decision on whether or not to get vaccinated?	Ordinal, 4 points Likert scale for frequency: Often (4), Sometimes (3), Rarely (2), Never (1)
Beliefs about vaccination	How much do you agree with the following statements: ‘I am not favorable to vaccines because they are unsafe’ ‘There is no need to vaccinate because natural immunity exists’	Ordinal, 4 points Likert scale for agreement: Totally (1), A little (2), Partially(3), Not at all (4)
COVID-19 vaccines attitudes (2020 version)	About future COVID-19 vaccines: Will be possible to produce safe and efficacious vaccines? Will you get vaccinated, if possible? Will Authorities succeed in vaccinating the entire population? Would you pay a fee to be vaccinated? Should children be vaccinated too?	Nominal YES/NO
Current vaccines behaviors (2020 version)	About current vaccines: Were you vaccinated against flu last season? Will you get vaccinated against flu this year? Do you plan to be vaccinated against other infectious diseases?	Nominal YES/NO
COVID-19 vaccines attitudes (2021 version)	About COVID-19 vaccines: …do you think the vaccines developed so far are safe? …do you think they are efficacious? ….do you think they overlap, regardless of the production technique used? …do you intend to get vaccinated against COVID-19? …. if you could, would you choose which vaccine to take? …will the Government be able to offer the vaccine against COVID-19 free for everyone? …would you pay a fee to be vaccinated? …should vaccination against COVID-19 be made mandatory for everyone? …should vaccination against COVID-19 be made compulsory for the most at-risk groups? …do you think children should be vaccinated too?	Nominal YES/NO
Current vaccines behaviors (2021 version)	About current routine vaccines: …have you been vaccinated against flu? …you wanted to be vaccinated against the flu, but you couldn’t? (Question included as In the 2020–21 season, as some Italian regions experienced shortage of influenza vaccine making it difficult to some to get immunized, despite the overall increase in vaccination rates (https://tg24.sky.it/salute-e-benessere/2020/11/30/vaccino-influenza-regioni (accessed on 5 February 2024)) …in 2020 you have been vaccinated and/or do you intend to vaccinate yourself soon against other infectious diseases, in addition to influenza and COVID-19?	Nominal YES/NO