Immunizations and Vaccinations

Types of Immunizations

At the core of families' concerns with vaccines is the very nature of the vaccines. Vaccines are one form of immunizations, and immunizations are biologic rather than pharmaceutical. Immunizations come from materials such as cells, tissues, or living organisms, unlike pharmaceuticals that come from chemical reactions and distillations of purified chemical reagents.

Immunizations consist of a wide variety of biologics but form two major categories related to their mechanisms of action. Immunizations are either active or passive. Active immunizations stimulate immune reactions resulting in persisting immunity. Passive immunizations provide temporarily materials that otherwise would be produced by immune reactions.

Both mimic a natural process that occurs when the body recognizes foreign materials or antigens. These are usually part of the surface structure of germs, such as bacteria or virus. These antigens are specific to the type of germ. They stimulate the immune systems to manufacture antibodies (or immunoglobulins). Antibodies are special proteins that interact with disease-specific antigens carried by the germs themselves. That interaction leads to further immunologic activity against the antigens and the bacteria or viruses presenting the antigen, which leads to the destruction or neutralization of that bacteria or virus.