I know. And in one of them, someone was permanently weakened by rheumatic fever, and I pronounced it wrong, and, after my mother corrected me with some amusement, she explained about why I'd never heard of it or known anybody in real life who had it -- it was because when we got strep throat, we had antibiotics that would clear it up in a couple of days, and that was a thing that happened with untreated strep, before antibiotics.

She explained about diphtheria, when Laura and Almanzo had it in The First Four Years, and all the childhood diseases they had in all the Betsy books (measles, mumps, German measles, the works) and the Great Brain books (another series!) and polio, too. She grew up pre-vaccine and lived through polio scares, and all I'd ever dealt with was chicken pox. I grew up thoroughly respecting the powers of vaccination.

The 1918 flu epidemic was very vividly in the All-Of-A-Kind Family books. I wish I'd thought to ask my grandmother about that, before she died. She would have been five, then.