Immunization: Nuisances No More

Immunization is the process by which complete resistance to a disease is achieved. This can be done simply by exposing the pathogen to the immune system once. During this primary exposure, adaptive immune system responses are sluggish and can only help in recovery. However, during any subsequent exposure, the immune system quickly recognizes the invader and destroys it before any symptoms can occur, preventing disease.

There are two types of active immunization: vaccination and natural. In both cases, the immune system is activated and generates it's own responses.

Vaccination is the intentional immunization against a specific disease. This is done with vaccines, which are substances that are similar to pathogens but do not produce the disease or its symptoms. There are two types of vaccines. There is the type that contains actual pathogenic organisms, but they have been chemically killed. The other type contains organisms that are still living, but they have been weakened genetically.

The other kind of active immunization is natural, in which the body naturally contracts the disease-causing agent and develops an immunity to it, so that it will quickly mount a disease-preventing response during any subsequent exposure.

This method does not involve a person's own immune system. Rather, antibodies produced by someone else's immune system is injected into a person when their own immune system cannot react in time to stop a rapidly spreading disease. The problem with this type of immunization is that since the person doesn't mount their own immune response, they do not develop an immunity to it, and therefore are just as susceptible to the disease the second time around as they were the first time. Also, if passive immunization is used too often, it can create side effects.