Abstract

The purpose of immunisation is to prevent people from getting sick. It helps to protect people against the complications of becoming ill, including developing chronic diseases, cancer, and death. Vaccines work by stimulating the body’s defence mechanisms to provide protection against infection and illness. These defence mechanisms are collectively referred to as the immune system. Vaccines mimic and sometimes improve the protective response normally mounted by the immune system after infection. The great advantage of immunisation over natural infections is that immunisation has a much lower risk of harmful outcomes.