system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: why is it better to get some diseases when you’re a child (chicken pox for instance) because they are less severe in childhood than adulthood? Especially when you consider that children have weaker immune systems than adults.
gpt
it is because adult chicken pox tends to cause complications like pneumonia and encephalitis while childhood chicken pox does not. Adults’ immune systems are stronger and employ more antibodies (rather than white blood cells) than children’s immune systems do, which is what triggers the immune response and the subsequent symptoms. 
Some strains of the flu are like this, too, such as the 1918 pandemic. The Spanish Flu killed young adults instead of the usual flu victims (old people and kids) because that strain triggered a severe immune reaction called a cytokine storm which basically shut down the bodies of infected people. A stronger immune system=stronger immune reaction=worse symptoms.