That’s what I’ve imagined when they state the kids have pre-existing conditions. When my son was young he had asthma, and every cold or virus was a “crisis.”
As to healthy immune system, this type of flu is thought to cause a cytokine storm, which can be more deadly in those with strong immune response than in those with a weakened immune response.
My nephew had a confirmed case of H1N1, but it was rather mild. He was put on Tamiflu and was back in school in a few days.
That is thought to be why the flu pandemic of 1916-18 killed off so many 20-30 something year olds. Strong immune systems. Kids got off easy because their immune systems are still developing. Geezers, such as myself, have immune systems that are “going away”. A strong immune system is not necessarily the best path to survival, just as thoroughbreds are not the healthiest horses.
The best path to long term survival is being average. At either side of the Bell curve lies death.
I wish they'd just state what the condition is. As parents, we would react differently hearing that the pre-existing condition was asthma vs cerebral palsy.
I haven't seen one article mentioning smoking as a factor, which by any account, it seems it should be.