This is bad, of course. But I feel like you buried the lede. Did she have monkeypox?
>it’s possible that it is only considered rare because they’re not testing.
Unlike COVID-19, monkeypox has frank symptoms (welts) that clearly distinguish it from other diseases. It cannot be mistaken for much else. Therefore, only a certain fraction of cases (the least severe) are even candidates to be missed, since I find it hard to believe that even the "medically reluctant" would not visit a doctor when they find themselves developing a monkeypox rash.
EDIT: to another poster's comparison with AIDS, it's my understanding that the incubation period for monkeypox is not months long as happens with HIV, either.