Immunisations: what is immunisation?

Immunisation is one of the most important weapons for protecting individuals and the community from serious diseases. Before the development of safe and effective vaccines, a quarter of a million children were affected by measles every other year and epidemics of poliomyelitis affected many thousands in the UK.

Vaccination is used to refer to all procedures for immunisation. The aim of a vaccination programme is to reduce the incidence of, or to, eliminate a particular disease. Immunisation has both a direct and indirect effect. The direct effect is the protection induced in the individual receiving the immunising agent. The indirect effect is the reduction of the incidence of the disease in others, the so called ‘herd immunity’. The Department of Health publication Immunisation against Infectious Diseases (the 'Green Book’) (412kB)  details the history of immunisation and immunisation advice over the years since this kind of preventative treatment was first used in 1786.