Natural immunity is part of human physiology. The immunity passed from a mother to the fetus during pregnancy or when breastfeeding is called natural passive immunity. If a child is infected with...

Natural immunity is part of human physiology. The immunity passed from a mother to the fetus during pregnancy or when breastfeeding is called natural passive immunity. If a child is infected with chickenpox by being exposed to another child with chickenpox and then develops antibodies against Varicella, this is naturally acquired active immunity.