Vaccines and Immunization

Bacterial and Viral Vaccines

Vaccination can be defined as active immunity produced by vaccine. It is immunity and immunologic memory similar to natural infection but without risk of disease. There are two basic types of vaccines: live attenuated and inactivated. Live attenuated vaccines are produced by modifying a disease-producing virus or bacterium in a laboratory. Vaccines derived from bacterium is called as bacterial vaccine and from virus is as viral vaccine. The resulting vaccine organism retains the ability to replicate and produce immunity, but usually does not cause illness. Inactivated vaccines can be composed of either whole viruses or bacteria, or fractions of either.