Sure, but imagine it’s only 20 percent. That’s still disastrous. On the other hand, I am sure in 3 generations the survivors will have excellent immunity against the bird flu.

The issue of the developing nations is not as valid as one might think - if one looks up the case reports mentioned in the study(P.50&ff) some of them have been treated with the full scale of modern critical care, in one case including ECMO and treatment also often included the current antiviral protocols according to the current guidelines at the times of the infection. (Which often actually were not recommended at the times during pregnancy due to the high likelihood of fetal developed damage.

While of course it can be argued that the accessibility of care might have been worse in these countries and treatment might have been started later (some case reports are inconclusive on that) the same is often the case in US case reports for the very same reasons.

The small number of patients included is also a bit of an issue, but there are simply not many reports available - the author did even include chinese-only reports in her study, so it's not for a lack of trying. This is sadly often a problem in emerging diseases, as they provide very low case numbers in the beginning or over their whole lifetime.

Additionally the scientists in the PRC since COVID are far more cautious what they publish, if they publish at all. And sadly most of the high quality papers on bird flu before COVID came from there.

Shitty situation and highly concerning.

90% in a small sample size isn't going to magicslly become 10% in the general population, and even if it did 10% is still a very high death rate.