Immunization is a mass means of protecting greatest number of people. For this, immunization has to be planned according to the needs of the situation; this is called immunization programme.
Vaccine is a preparation consisting of weakened germs or germ substances of a disease which on injection into a healthy person helps develop immunity by formation of antibodies.
Vaccine is a biological preparation that improves immunity to a particular disease. Vaccines are generally made from weakened (attenuated) or killed forms of disease causing microbes or the proteins present on their surface. On injection in healthy human, these weakened or killed microbes (vaccine) are recognized as foreign substance by the immune system. The Immune system destroys it and keeps a record of it, in order to deal with it faster if encountered in future.
Types of vaccines
Types of Vaccines There are several basic types of vaccines. Some are described below
Attenuated vaccines : These are prepared from living but attenuated (weakened) microbes. Example - Sabin polio.
Inactivated vaccines : These are prepared from killed microbes. Example - Salk polio, rabies etc.
Toxoids : These are prepared from inactivated toxins of the pathogen (bacteria or virus). Example - vaccine against tetanus and diphtheria.
Subunit vaccines : These are prepared from only those fragments of a microorganism that best stimulates the immune system. Example - Hepatitis B vaccine.
Conjugated vaccines : These are prepared by combining polysaccharides with proteins. It is used to deal with poor immune response of children.
1. Immunisation is developing resistance to disease-producing germs or their toxins by introducing killed germs or germ substance to induce the production of specific antibodies.