It's a viral illness
It used to be extremely common, but isn't anymore now that we vaccinate against it.
Prior to the vaccine, 100-200 children
per year died in the USA as a result of complications of chicken pox. That number is now much lower. Once you have chicken pox, you have it forever. The virus
lies dormant near your spinal cord, and sometimes reactivates. When it reemerges, it's called shingles