Immunity keeps us safe from being sick. There are several types of immunity: passive, active, and community immunity. In passive immunity, the antibodies are generated in another host. It could be natural, from mother to an unborn baby or to a newborn baby through breast milk or artificial, where antibodies could be injected into the body. This type of protection is immediate but lasts for a few weeks or months. However, active immunity includes natural immunity which could be acquired through exposure to the disease or vaccine-induced immunity which involves exposure to killed or weakened form of the disease-causing organisms. However, herd immunity applies to situations where enough people in the community are exposed to the pathogen and this, in turn, slows down the spread of the pathogen. This type of immunity is indirect and is one of the least reliable.