Oh I mean thinking that just because you aren't at risk you don't need the vaccine. I think the twins were mistaken of course, given their age. But for example, myself being younger and healthy I believe I'm also low risk. But I am still relieved to be vaccinated. I know people who still have breathing issues because they caught it and it continues to impact them months after recovering from the virus itself.

I read "this kind of thinking" as relating to the quote from the parent comment, talking about the mindset of people who avoid the vaccine because they insist they are not at risk of severe illness or death, despite being members of a population who demonstrably are.