The body develops antibodies after infection or exposure to a virus. These antibodies respond when the person is infected again and fight off the infection. For example, when you have chicken pox, your body develops immunity to it by developing antibodies. Upon subsequent exposure, your body's antibodies will fight this infection so that you are unable to be infected with it again.
Passive immunity occurs when a mother passes immunity or antibodies to something to her child during pregnancy. When the child is first born, these antibodies keep the child from becoming infected with many common viruses and passing away early. Some of the antibodies are only temporary and some others are fairly permanent. So, an infant is less likely to get sick in the first few months of life, however over time, the antibodies decrease and the child has to build up its own by being exposed to such viruses. This is a natural mechanism of protection from mother to infant.
· 8 years ago