Editing Immunization (section)

==Passive and active immunization==
[[File:National Immunization Campaign in "San Miguel Topilejo".JPG|thumb|Medical student participating in a polio vaccine campaign in Mexico]]
Immunization can be achieved in an active or passive manner: vaccination is an active form of immunization.

===Active immunization===
{{Main|Active immunity}}
[[File:Simplified Immunization Diagram.jpg|thumb|A simplified diagram showing the process of immunization through the production of anti-bodies]]
Active immunization can occur naturally when a person comes in contact with, for example, a microbe. The immune system will eventually create antibodies and other defenses against the microbe. The next time, the immune response against this microbe can be very efficient; this is the case in many of the childhood infections that a person only contracts once, but then is immune.

Artificial active immunization is where the microbe, or parts of it, are injected into the person before they are able to take it in naturally. If [[attenuated vaccine|whole microbes are used]], they are pre-treated.

The importance of immunization is so great that the American [[Centers for Disease Control and Prevention]] has named it one of the "Ten Great Public Health Achievements in the 20th Century".<ref name=CDC>[https://www.cdc.gov/about/history/tengpha.htm "Ten Great Public Health Achievements in the 20th Century".] {{Webarchive|url=https://web.archive.org/web/20160313072852/http://www.cdc.gov/about/history/tengpha.htm |date=2016-03-13 }} [[Centers for Disease Control and Prevention|CDC]]</ref>
Live attenuated vaccines have decreased pathogenicity. Their effectiveness depends on the immune systems ability to replicate and elicits a response similar to natural infection. It is usually effective with a single dose. Examples of live, attenuated vaccines include [[measles]], [[mumps]], [[rubella]], [[MMR vaccine|MMR]], [[yellow fever]], [[varicella]], [[rotavirus]], and [[Live attenuated influenza vaccine|influenza]] (LAIV).

===Passive immunization===
{{Main|Passive immunity}}
Passive immunization is where pre-synthesized elements of the immune system are transferred to a person so that the body does not need to produce these elements itself. Currently, [[antibodies]] can be used for passive immunization. This method of immunization begins to work very quickly, but it is short lasting, because the antibodies are naturally broken down, and if there are no B cells to produce more antibodies, they will disappear.

Passive immunization occurs physiologically, when antibodies are transferred from mother to [[fetus]] during [[pregnancy]], to protect the fetus before and shortly after birth.

Artificial passive immunization is normally administered by [[Injection (medicine)|injection]] and is used if there has been a recent outbreak of a particular disease or as an emergency treatment for toxicity, as in for [[tetanus]]. The antibodies can be produced in animals, called "serum therapy," although there is a high chance of [[anaphylactic shock]] because of immunity against animal serum itself. Thus, [[humanized antibodies]] produced ''[[in vitro]]'' by [[cell culture]] are used instead if available.