I'm one of those people (knock on wood) who never gets sick. I never get colds or seasonal flu, and I don't get routine flu vaccines. Never got COVID either, even when several people in the house had it (I did get the J&J vaccine for that, however).

I did have chicken pox as a kid, but have not had shingles nor the vaccine (yet). A co-worker was laid up for a week after his shingles vaccine, but that's obviously just one data point.

But, I've been considering getting the Shingrix series even if I have to pay for it. I turn 60 this year. Shingles doesn't sound fun.

I wonder if infections do not cause more dementia, but are simply correlated with more. A weaker immune system may trigger many many things.

And similar questions about obesity "causing" many diseases, sunburns causing skin cancer (although that sounds somewhat plausible) etc.

>Replicated association [...]

"association" undersells it a bit, because the data is better than the typical cohort study, which has issues like "what if people who got the vaccine are also richer and care about their health more?". There's quasi-randomization going on. From the more in depth article that's linked:

>Research is also revealing unexpected interventions that help to keep ageing minds sharp. One of the most promising derives from an analysis by Pascal Geldsetzer of Stanford University and his team of a natural experiment in Wales. In 2013 the British region started offering people aged 70-79 free vaccinations through the public-health system. This change resembled an RCT, in that a large number of people were separated almost at random into two groups: those who had already turned 80 in the weeks before the programme started, and so were not eligible to be jabbed; and those who turned 80 in the weeks after, roughly half of whom were duly vaccinated.

> like the more colds you have in life

Whoa wait what? This is the first time I’ve heard of this - is this actually common knowledge?