An example of passive immunity occurs naturally in unborn babies due to the mother's antibodies and white cells crossing the barrier of the placenta. Passive immunity is defined as one person receiving antibodies from someone else, resulting in short-term protection from certain types of infectious diseases.
Another example of passive immunity takes place when newborns drink colostrum from their mother. Colostrum contains antibodies to protect the newborn in the first few weeks of life before they are able to produce their own antibodies.
An advantage of passive immunity is that protection begins quickly, often within hours. A disadvantage is that the protection is short term.