Table 2.

Overview of illustrative quotes

Main theme	Sub-theme	Illustrative quote(s)
Attitude towards vaccination		1. “Let them inject, if it doesn't help, it won't harm.” (NL, 70+) 2. “I do it too, why you never know.” (IT, 50-64)
Perceptions regarding infectious diseases	Perceived severity of the disease	3. “it [herpes zoster] is painful, it seems that someone is tearing you from the inside ...” (IT, rural, mixed ages) 4. “Because yes, I simply let myself be vaccinated. Because I think, I won’t die from the vaccine, but I might die from that flu (NL, 65-69)
	Perceived susceptibility	5. “Yes, then surely you would be more courageous to ask for it, if it showed that, yes, there is a good chance you would get it, you would go sooner.” (HU, mixed ages) 6. “I was not vaccinated because I said "I am not susceptible to flu"” (IT, 70+) 7. “ … there is always the idea that " this doesn't happen to me "…. There is always this thought.” (IT, rural, mixed ages)
	Experience with infectious diseases	8. “I am not against it, I mean if I get sick this year or the next, I will definitely get it the following year.” (NL, rural, mixed ages)
Perceptions regarding vaccines	Perceived effectiveness to prevent disease and overall effects	9. “I always refer to the professor, 50% success, no more. It's not huge but it's still worth the cost to try.” (FR, mixed ages) 10. “Nor does the seat belt provide 100 percent protection.” (HU, 50-64)
	Perceived side effects	11. “Well I think if you really induce a real disease with it, then I would say well then rather omit it. Because then I actually think what you offer, gives you more problems. Because that means, because if you, especially if you are in a vulnerable group, give it to people, that means that they will be made sick by you at that moment. Instead of giving something to prevent disease. And then I think yes, then you have to think three times before you try that.” (NL, 65-69)
	Vaccine safety	12. “You are taking a small, but real, personal risk by getting vaccinated. From a public health point of view, it is very effective, but for your personal case, it is possibly very bad.” (FR, mixed ages). 13. “it is not just being marketed uh nowadays, so it takes a lot of time and research and especially in the Netherlands, yes” (NL, 50-64)
Perceptions on the prevention of infectious diseases in general		14. “If it [disease] comes then it comes” (NL, 70+) 15. “of course you are allowed to die, but if you have a pneumonia, severe pneumonia and after that you are really much less and you would have had a choice in that, then I think you would have made that choice differently in advance.” (NL, 50-64) 16. “so, you actually have to be in advance with your own decisions like what would I want, what are the possibilities for that, is it also offered to me in it” (NL, 50-64)
	Social responsibility in vaccination	17. “And that I just don't know if I'd always want to do that. Because you can't protect the whole world and I don't want to protect the whole world.” (NL, 50-64)
	Mandatory versus freedom of choice	18. “when they are in nursing homes, it is an obligation. They have no choice.” (FR, mixed ages)
Role of age/health in vaccine acceptance		19. “my mother was 94 and at a certain point I think, yes you know, life is also finite at some point. And do you still have to have that woman vaccinated, for God knows what? (NL, 50-64) 20. “you have to die of something.” (FR, mixed ages) 21. “that are always pneumococci, that is an old man's friend. Because you can't die in a nicer, faster way than that way.” (NL, 65-69) 22. “I get the flu vaccine every year, as prescribed by the doctor because of various diseases ... I have enough of what I have and the flu or even a cold can be a problem for me.” (IT, rural, mixed ages) 23. “I never did it because for the moment I think my body can afford not to do it…” (IT, 70+) 24. “I do not do it now because I feel well” (IT, 50-64) 25. “She got the flu shot because she is at risk. Diabetic, etc. I have nothing, so I see no use.” (FR, mixed ages) 26. “but I wait until I will be 65 years old and then I will decide ... concerning prevention” (IT, rural, mixed ages) 27. “Yes, maybe that you then still and cherish your health more […] I hope not of course, but you will lose some of the physical health. And well, all in all, I think maybe you’ll be more open to indeed the call for such a flu vaccination”. (NL, 65-69)
	Vaccination as part of Healthy Ageing	28. “vaccinations are part of those important actions you can do to take care of yourself, and they allow you to arrive at old age certainly in a more discreet way” (IT, 70+) 29. “Healthy aging means more to yes ensuring that you keep moving, that you have good nutrition and things like that. Not with vaccinations.” (NL, 70+)
Access to vaccination		30. “for the flu vaccine, at one point the employers were proactive because it less disturbed the operation of the company.” (FR, mixed ages)
External influences	HCPs	31. “I think that compared to the vaccine, the medical world itself is not entirely in favour, so there might be dangers. They do not all agree, that means that there are risks. Or that the side effects are not entirely elucidated.” (FR, mixed ages)
	Other	32. “So, I think that anything that can help you feel more fit physically, not to run any risks, not to get into that pointer corner at work. That I would like to use that yes.” (NL, 50-64) 33. “but such a such a herpes, I have seen that with my own eyes when I worked in the health care among older adults, and I think yes you don’t wish that on anyone.” (NL, 65-69) 34. “He doesn't want to go get vaccinated because his mother, when she was alive, she had to die in '85, she got vaccinated and she got sick. So, he says, no!” (FR, mixed ages) 35. “I haven't met anyone who had serious side effects. What people see on Facebook and what they see in the press, I always like to highlight a press, if there is one, they are sure to push it and push it for a week so everyone knows.” (HU, 50-64)
Information provision		36. “Me, I tend not to bother my mind, I trust the doctor. They tell me for your well-being, it would be rather good for you to do that, it doesn't cost me much to do it.” (FR, mixed age) 37. “because when we have doctors or health care workers (HCW) who tell you ‘look, this is the path you must follow’ ... so convince yourself that to get to that famous old age we would all like to get to, this is the path you must follow. So it would be necessary also a little care from our side, to follow the doctors and to follow the HCW…” (IT, 65-70)