Immunization is the process whereby a person is made immune or resistant to an infectious disease.

Immunization is a proven tool for controlling and eliminating life-threatening infectious diseases and is estimated to avert over 2 million deaths each year. It enables the body to better defend itself against diseases caused by certain bacteria or viruses, and is one of the most cost-effective health investments, with proven strategies that make it accessible to even the most hard- to-reach and vulnerable populations.

Immunization may occur on its own (when people are exposed to bacteria or viruses), or typically by the administration of a vaccine. When people are immunized against a disease by the administration of a vaccine, they do not get the disease or get only a mild form of it.

Vaccines stimulate the body’s own immune system to protect the person against subsequent infection or disease. It has clearly defined target groups. It can be delivered effectively through outreach activities; and vaccination does not require any major lifestyle change.