Dying of the flu isn't visceral enough to grab the imagination. It would be scarier if we were living in medieval Europe and we personally know friend and families that were killed off by the Plague, but in modern society it's too removed of a threat to really strike fear in children's hearts.

Of my grandfather's family, of his nine siblings, two survived. All of them where strong and healthy, late-twenties to early thirties, and died within three days. We elide over the impact of that event to rather focus on the notion that such concept are safely 'in the past'.

“…every, nearly every porch, every porch that I’d look at had–would have a casket box a sittin’ on it. And men a diggin’ graves just as hard as they could and the mines had to shut down there wasn’t a nary a man, there wasn’t a, there wasn’t a mine arunnin’ a lump of coal or runnin’ no work. Stayed that away for about six weeks.”[1]

On another note, the Spanish flu is responsible for Americans' shift from 'parlor' to 'living room'[2]

[1] https://www.appalachianhistory.net/2017/10/great-pandemic-of...

[2]https://blogsurabhi.wordpress.com/2013/03/09/what-is-the-ori...

Your grandfather's family isn't the modern world that children today know. Incidents from a century ago are hard to relate to someone who knows only modern medicine and sanitation.

Did the people from a century ago feel like they were in a low-tech time where medical solutions hadn't been invented yet? I suspect they felt like they were at the very front of modern life and were reaping the benefits of modern knowledge and technology. Then, suddenly something new and unexpected came along and revealed how fragile they really were.

Today we might also feel that we're at the very front of modern life and reaping the benefits of modern knowledge and tech. However, even our great county of Los Angeles has been taken over by a new mosquito that is hurting our quality of life:

https://www.glacvcd.org/vector-information/mosquitoes/invasi...

https://abc7.com/health/ankle-biter-mosquitoes-more-common-i...

As far as I'm aware, we have no practical solution for this new problem.

Ah, but now you prove my point.

In the comment section about an article on how children perceive the world?

I’d say disease is a lot more visceral than something like climate change. The former can affect you, personally, on a time scale you can perceive while the latter doesn’t, for the most part.