Yes, dialysis is surprisingly good at filtering out viral particles, but... that's not desirable in this case. After all these viruses are carrying the therapeutic payload, if you filter them out then you might as well not introduce them in the first place.

I imagine if these deaths could have been prevented by this one-line HN comment, they would have thought of it.

Maybe a better phrasing of your question would be:

> Why is hemodialysis ineffective for this?