Comments by "Vary Olla" (@varyolla435) on "The Return of the Black Death: The Plague of Children" video.

First is that immunity is not hereditary. Most immunity you develop in life as a response to being infected with something will be temporary. After a time depending upon many variables your antibody generation usually wanes leaving you vulnerable again. So regardless of what the parents were immune to their child when born is born with essentially "a blank slate". It obtains some antibodies prior to birth but since the mother's immune system created those rather than the child's they will in time break down leaving the child only it's underdeveloped immune system to try to protect it.
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