[EvaH (OP)]

David asks:

Dexamethasone has been hugely effective in damping down the covid 19 cytokine storm, saving thousands of lives. As I understand it, the cytokine storm is more potent in young adults with more efficient immune systems. Why then is it mainly the over 70s, with already diminished immune systems, most severely affected? If the "weak immune system" was the reason surely babies would suffer equally? Could there be a reason related to previous exposure to another pathogen, with peak circulation around 70 years ago, which either weakens or possibly supercharges the immune response?

What do you think?

[alancalverd]

The "other pathogen" is mostly pneumonia. It's pretty rife in old folks' homes, which is why discharging known infectious patients into nursing homes was a criminal act.

[Petrochemicals]

If the "weak immune system" was the reason surely babies would suffer equally?

Babies and young children have a good immune system that is eager to learn. It is not that strong though and not experienced.

[set fair]

Why are the over 70s the most severely affects with COVID?

Probably because kids are good with the T cells and poor with antiodies while oldsters have a poor T cell response made worse by the widesperead Vitamin D deficiecy.

https://academic.oup.com/immunotherapyadv/article/1/1/ltaa008/5999967?login=true