Covid more than once?

Just read an article saying that 2/3 of people with Omicron have had covid before.

I, like many GN members, have never had covid. I just wonder if maybe some (certainly not all and this isn't an accusation or judgement) of those who've had it more than once are less careful and take less precautions?

Some people have no choice. They are vulnerable because of their job or due to family (with teenagers at school for example). But a couple of young adults I know have continued their lives as near to normally as they have been able (including travel overseas during lockdown). No surprise they've had it more than once.

Opinions?

www.standard.co.uk/news/health/react-study-imperial-college-coronavirus-omicron-reinfected-schoolchildren-b978820.html