This was an odd one. Young and healthy people seemed to suffer worse. IIRC, the virus utself attacks the white blood cells.
So people who are healthy and have strong immune systems produce the most amount of white blood cells. And give the virus lots of lunch.
The other thing was the fantastic quickness it killed folks. It was not unusual for a person to wake up in the morning feeling fine and be cold and dead before midnight that same day.
My mother's father died of it when she was one. My grandmother said, "He had a sore throat and three days later he was dead."
Recently found out through the Internet that my father's father's brother also died of it. I got a query from someone about his grandfather, who died around 1920 or 1921. When I asked my father, he remembered: "He died of the flu."
Do you know if people who actually came down with this flu ever lived?