Difference between revisions of "Immunization" - New World Encyclopedia

Revision as of 11:32, 2 August 2007

A child being immunized against polio.

For financial immunization, see Immunization (finance).

Immunization, or immunisation, is the process by which an individual is exposed to an agent that is designed to fortify his or her immune system against that agent. The material is known as an immunogen. Immunization is the same as inoculation and vaccination in that inoculation and vaccination use a viable infecting agent like immunization does. When the human immune system is exposed to a disease once, it can develop the ability to quickly respond to a subsequent infection. Therefore, by exposing an individual to an immunogen in a controlled way, their body will then be able to protect itself from infection later on in life.

History of immunization

While Dr. Edward Jenner (1749-1823) has been recognized as the first doctor to give sophisticated immunization, it was British dairy farmer Benjamin Jestey who noticed that "milkmaids" did not become infected with smallpox, or displayed a milder form. Jestey took the pus from an infected cow's udder and inoculated his wife and children with cowpox, thereby making them immune to smallpox.

By injecting a human with the cowpox virus (which was harmless to humans), Jenner swiftly found that the immunized human was then also immune to smallpox. The process spread quickly, and the use of cowpox immunization has led to the almost total eradication of smallpox in modern human society. After successful vaccination campaigns throughout the 19th and 20th centuries, the World Health Organization (WHO) certified the eradication of smallpox in 1979.

Required immunizations upon entry to school

In the USA each state provides school districts with an obligation to regulate those eligible to enter public schooling. Since schools are congregate settings, and thus communication of diseases is a consideration, school districts may exclude children who seek to attend without the protection of certain immunizations.

For example, in the state of Ohio, USA, each student is required to provide proof of specific immunizations or have an authorized waiver from the requirement upon entry to school at age 6 years. If a student does not have the necessary immunizations or a waiver acceptable to the state, the school principal may refuse entry and require compliance with a set deadline. This procedure is for the safety of all students and follows Ohio State law.

Unless given a waiver, students must meet the following requirements:

DPT (Diphtheria, pertussis, tetanus)—Five doses if the fourth one was before the fourth birthday.
Measles—Two doses, the first one after 12 months of age, and the second at least 28 days after the first birthday.
Rubella—Same as measles.
Mumps—Same as measles.
Polio—Four doses if the third was before the fourth birthday.
Hepatitis B—For students starting kindergarten.

Additionally, for schools offering a pre-school program, add the requirements for two doses of haemophilus influenzae.

Passive and active immunization

Passive immunization

Passive immunization is where pre-made antibodies are given to a person. This method of Immunization begins to work very quickly, but it is short lasting, because the antibodies are naturally broken down, and not stored for later use. It can also result in serum sickness and anaphylaxis.

Passive immunization can be naturally acquired when antibodies are being transferred from mother to fetus during pregnancy, to help protect the fetus before and shortly after birth.

Artificial passive immunization is normally given by injection and is used if there has been a recent outbreak of a particular disease or as an emergency treatment to poisons from insects etc. The antibodies are normally produced in animals and injected into humans.

Active immunization

Active immunization is where the actual microbe is taken in by a person. Antibodies are created by the recipient and are stored permanently.

Active immunization can occur naturally when an untreated microbe is received by a person who has not yet come into contact with the microbe and has no pre-made antibodies for defense. The immune system will eventually create antibodies for the microbe, but this is a slow process and, if the microbe is deadly, there may not be enough time for the antibodies to begin being used.

Artificial active immunization is where the microbe is injected into the person before they are able to take it in naturally. The microbe is treated, so that it will not harm the injected person. Depending on the type of disease, this technique also works with dead microbes, parts of the microbe, or treated toxins from the microbe.

External Links

Vaccination/Vaccine (and Immunization, Inoculation. See also List of vaccine topics and Epidemiology)

Development: Models - Timeline - Toxoid - Trial

Administration: ACIP - GAVI - VAERS - Vaccination schedule - VSD

Specific vaccines: Anthrax - BCG - Cancer - DPT - Flu - HIV - HPV - MMR - Pneumonia - Polio - Smallpox

Controversy: A-CHAMP - Anti-vaccinationists - NCVIA - Pox party - Safe Minds - Simpsonwood - Thimerosal controversy - Vaccine injury

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-[[Image:Poliodrops.jpg|right|thumb|A child being immunized against [[Polio]].]]
+[[Image:Poliodrops.jpg|right|thumb|A child being immunized against [[polio]].]]
 :''For financial immunization, see [[Immunization (finance)]].''
-'''Immunization''', or '''immunisation''', is the process by which an individual is exposed to an agent that is designed to fortify his or her immune system against that agent. The material is known as an [[antigen|immunogen]].  Immunization is the same as [[inoculation]] and [[vaccination]] in that inoculation and vaccination use a viable infecting agent like immunization does. Immunization is just the general term for vaccination and such things as what you gain from these proccess.
+'''Immunization''', or '''immunisation''', is the process by which an individual is exposed to an agent that is designed to fortify his or her immune system against that agent. The material is known as an [[antigen|immunogen]].  Immunization is the same as [[inoculation]] and [[vaccination]] in that inoculation and vaccination use a viable infecting agent like immunization does.
 When the human immune system is exposed to a disease once, it can develop the ability to quickly respond to a subsequent infection.  Therefore, by exposing an individual to an immunogen in a controlled way, their body will then be able to protect itself from infection later on in life.
-{{Vaccines}}
+== History of immunization ==
+While Dr. [[Edward Jenner]] (1749-1823) has been recognized as the first doctor to give sophisticated immunization, it was British dairy farmer Benjamin Jestey who noticed that "milkmaids" did not become infected with [[smallpox]], or displayed a milder form.  Jestey took the pus from an infected cow's udder and inoculated his wife and children with cowpox, thereby making them immune to smallpox.
-'''Vaccination''' is the process of administering weakened or dead pathogens to a healthy person, with the intent of conferring immunity against a targeted form of a related disease agent.
-The term was coined by [[Edward Jenner]] and adapted by [[Louis Pasteur]] for his pioneering work in vaccination. Vaccination ([[Latin]]: ''vacca&mdash;[[cow]]'') is so named because the first [[vaccine]] was derived from a [[virus (biology)|virus]] affecting cows: the [[cowpox]] virus, a relatively benign virus that provides a degree of immunity to [[smallpox]], a contagious and deadly disease.  In common speech, 'vaccination' and 'immunization' generally have the same colloquial meaning.  Vaccination efforts were [[anti-vaccinationists|initially met with some resistance]] before early success brought widespread acceptance and mass vaccination campaigns were undertaken.
-The eradication of [[smallpox]], which was last seen in a natural case in 1977, is considered the most spectacular success of vaccination.  Some people assert that childhood vaccination plays a role in [[autoimmune disease]] and [[autism]], though large-scale scientific studies have not shown any link.
-==Triggering immune sensitization==
-In the generic sense, the process of [[artificial induction of immunity]], in an effort to protect against [[infectious disease]], works by 'priming' the [[immune system]] with an '[[immunogen]]'.  Stimulating immune response, via use of an infectious agent, is known as ''[[immunization (medicine)|immunization]]''.  Vaccinations involve the administration of one or more immunogens, in the form of live, but weakened ([[attenuated]]) infectious agents, which normally are either weaker, but closely-related species (as with smallpox and cowpox), or strains weakened by some process.  In such cases, an immunogen is called a ''[[vaccine]]''.
-Some modern vaccines are administered after the patient already has contracted a disease, as in the cases of experimental [[AIDS]], [[cancer]] and [[Alzheimer's disease]] vaccines.  Vaccinia given after exposure to smallpox, within the first four days, is reported to attenuate the disease considerably, and vaccination within the first week is known to be beneficial to a degree.  The first Rabies immunisation was given by Pasteur to a child bitten by a rabid dog, and then and subsequently post-exposure immunisation to Rabies has generally been followed by survival.  The essential empiricism behind such immunizations is that the vaccine triggers an immune response more rapidly than the natural infection itself.
-Most vaccines are given by hypodermic injection as they are not absorbed reliably through the gut.  Live attenuated Polio, some Typhoid and Cholera Vaccines are given orally in order to produce immunity based in the bowel.
-==History of vaccinations==
-Vaccination campaigns have spread throughout the globe since Jenner's smallpox vaccine of 1796, sometimes prescribed by law or regulations (See [[Vaccination/Vaccination acts|vaccination Acts]]).  Vaccines are now used to fight a wide variety of disease threats besides [[smallpox]].  [[Louis Pasteur]] further developed the technique during the 19th century, extending its use to protecting against bacterial [[anthrax disease|anthrax]] and viral [[rabies]].  The method Pasteur used entailed  treating the infectious agents for those diseases so they lost the ability to cause serious disease.  Pasteur adopted the name ''vaccine'' as a generic term in honor of Jenner's discovery, which Pasteur's work built upon.
-Prior to vaccination with cowpox, the only known protection against smallpox was ''[[inoculation]]'' or ''variolation'' (Variola - the Smallpox viruses) where a small amount of live smallpox virus was administered to the patient;  this carried the serious risk that the patient would be killed or seriously ill.  The death rate from variolation was reported to be around a tenth of that from natural infection with Variola, and the immunity provided was considered quite reliable.  Factors contributing to the efficacy of variolation probably include the choices of Variola Minor strains used, the relatively low number of cells infected in the first phase of multiplication following initial exposure, and the exposure route used, via the skin or nasal lining rather than inhalation of droplets into the lungs.
-Consistency would suggest the activity should have predated Jenner's description of an effective vaccination system, and there is some history relating to opposition to the older and more hazardous procedure of variolation.
-In modern times, the first vaccine-preventible disease targeted for eradication was smallpox. The World Health Organization coordinated the global effort to eradicate this disease. The last naturally occurring case of smallpox occurred in Somalia in 1977.
-In 1988, the governing body of W.H.O. targeted polio for eradication by the year 2000. Although the target was missed, eradication is very close. The next eradication target would most likely be measles, which has declined since the introduction of measles vaccination in 1963.
-In 2000, the [[Global Alliance for Vaccines and Immunization]] was established to strengthen routine vaccinations and introduce new and under-used vaccines in countries with a per capita GDP of under US$1000. GAVI is now entering its second phase of funding, which extends through 2014.
-==Compulsory vaccination and opposition to vaccination==
+By injecting a human with the cowpox virus (which was harmless to humans), Jenner swiftly found that the immunized human was then also immune to smallpox. The process spread quickly, and the use of cowpox immunization has led to the almost total eradication of smallpox in modern human society. After successful vaccination campaigns throughout the 19th and 20th centuries, the World Health Organization (WHO) certified the eradication of smallpox in 1979.
-In an attempt to eliminate the risk of outbreaks of some diseases, several governments and other institutions have instituted policies requiring vaccination for all people. For example, an 1853 law required universal vaccination against smallpox in [[England]] and [[Wales]], with fines levied on people who did not comply. In the United States, the [[United States Supreme Court|Supreme Court]] ruled in the 1905 case ''Jacobson v. Commonwealth of Massachusetts'' that the state could require individuals to be vaccinated for the common good. Common contemporary vaccination policies require that children receive common vaccinations before entering school. Compulsory vaccination is believed to have greatly reduced the rates of some infectious diseases.<ref name="Salmon2006">Salmon, Daniel A ''et al''. (2006) Compulsory vaccination and conscientious or philosophical exemptions: past, present, and future. ''The Lancet'' 367(9508):436-442.</ref>
-Beginning with early vaccination in the nineteenth century, these policies led to resistance from a variety of groups, collectively called [[anti-vaccinationist]]s, who objected on ethical, political, medical safety, [[vaccination and religion|religious]], and other grounds. Common objections are that compulsory vaccination represents excessive government intervention in personal matters, or that the proposed vaccinations are not sufficiently safe. Many modern vaccination policies allow exemptions for people who have compromised immune systems, allergies to the components used in vaccinations or strongly-held objections.<ref name="Salmon2006"/>
+== Required immunizations upon entry to school ==
+In the USA each state provides school districts with an obligation to regulate those eligible to enter public schooling. Since schools are congregate settings, and thus communication of diseases is a consideration, school districts may exclude children who seek to attend ''without'' the protection of certain immunizations.
-==Herd immunity and medical risk management issues==
+For example, in the state of [[Ohio]], USA, each student is required to provide proof of specific immunizations or have an authorized waiver from the requirement upon entry to school at age 6 years. If a student does ''not'' have the necessary immunizations or a waiver acceptable to the state, the school principal may refuse entry and require compliance with a set deadline. This procedure is for the safety of all students and follows Ohio State law.
-Vaccination campaigns are generally accepted as having contributed to the worldwide elimination of [[smallpox]], through [[herd immunity]], and to the restriction of [[polio]] to isolated pockets in countries where healthcare access is difficult.  The [[risk management]] practices of government health agencies' promoting widespread vaccination campaigns has prompted increasing controversy in recent years, despite the fact that many once-common childhood diseases, such as [[mumps]], [[measles]] and [[rubella]], are now relatively rare in developed countries.
+Unless given a waiver, students must meet the following requirements:
-Nevertheless, vaccination campaigns may have unfortunate [[Co-evolution|co-evolutionary]] side-effects, particularly if they produce a selective pressure in favor of certain strains against which there are no vaccines or [[pharmacology|treatment]].  Another problem related to co-evolution is that vaccines that may eliminate one infectious diseases or another may, in turn, allow others to thrive in the [[ecological niche]] that has been vacated.  For example, it has been postulated that (the less-often-fatal) serogroup-B [[meningitis]] strains may expand into the niche provided if serogroup-C is largely eradicated through vaccination.  However, while there has been a rise in serogroup-B meningitis, there is as yet no evidence to link this to the meningitis-C vaccination.
+#'''DPT ([[Diphtheria]], [[pertussis]], [[tetanus]])'''—Five doses if the fourth one was before the fourth birthday.
+#'''[[Measles]]'''—Two doses, the first one after 12 months of age, and the second at least 28 days after the first birthday.
+#'''[[Rubella]]'''—Same as measles.
+#'''[[Mumps]]'''—Same as measles.
+#'''[[Poliomyelitis|Polio]]'''—Four doses if the third was before the fourth birthday.
+#'''[[Hepatitis B]]'''—For students starting kindergarten.
-An incompletely-successful attempt at eradication of a disease through vaccination might increase the [[mathematical modelling in epidemiology#The mathematics of mass vaccination|average age of contraction of the disease]].  In diseases such as [[measles]], where there is a higher rate of complication in older people, the overall effect might, in theory, be to cause more deaths than before the vaccination was introduced.  Potentially, this could be a '[[perverse effects of vaccination|perverse effect]]' of vaccination campaigns.  Observation of immunity levels in a population over many years has been followed by booster immunization programs, for instance, in the [[United Kingdom]], with measles and mumps.
+Additionally, for schools offering a pre-school program, add the requirements for two doses of [[haemophilus influenzae]].
-==Adjuvants and preservatives==
+==Passive and active immunization==
+===Passive immunization===
+Passive immunization is where pre-made [[antibodies]] are given to a person. This method of Immunization begins to work very quickly, but it is short lasting, because the antibodies are naturally broken down, and not stored for later use. It can also result in [[serum sickness]] and [[anaphylaxis]].
-Vaccines typically contain one or more [[adjuvants]], used to boost the immune response.
+Passive immunization can be naturally acquired when [[antibodies]] are being transferred from mother to fetus during pregnancy, to help protect the fetus before and shortly after birth.
-Tetanus toxoid for instance is usually adsorbed onto Alum.  This presents the antigen in such a way as to produce a greater action than the simple aqueous tetanus toxoid.  People who get an excessive reaction to adsorbed tetanus toxoid may be given the simple vaccine when time for a booster occurs.
-In the preparation for the 1990 Gulf campaign, Pertussis vaccine (not acellular) was used as an adjuvant for Anthrax vaccine.  This produces a more rapid immune response than giving only the Anthrax, which is of some benefit if exposure might be imminent.
+Artificial passive immunization is normally given by injection and is used if there has been a recent outbreak of a particular disease or as an emergency treatment to poisons from insects etc. The antibodies are normally produced in animals and injected into humans.
-They may also contain preservatives, which are used to prevent contamination with [[bacteria]] or [[fungi]]. Until recent years, the preservative [[thimerosal]] was used in many vaccines that did not contain live virus. [[As of 2005]], the only childhood vaccine in the U.S.A. that contains thiomerosal is the influenza vaccine [http://www.vaccinesafety.edu/thi-table.htm], which is currently recommended only for children with certain risk factors.<ref>Melinda Wharton. National Vaccine Advisory committee [http://www.hhs.gov/nvpo/vacc_plan/ U.S.A. national vaccine plan]</ref> The UK is considering Influenza immunisation in children perhaps as soon as in 2006-7.  Single-dose Influenza vaccines supplied in the UK do not list Thiomersal (its UK name) in the ingredients.  Preservatives may be used at various stages of production of vaccines, and the most sophisticated methods of measurement might detect traces of them in the finished product, as they may in the environment and population as a whole[http://www.npl.co.uk/environment/vam/nongaseouspollutants/ngp_metals.html].
+===Active immunization===
+Active immunization is where the actual microbe is taken in by a person. Antibodies are created by the recipient and are stored permanently.
-== Vaccine research ==
+Active immunization can occur naturally when an untreated microbe is received by a person who has not yet come into contact with the microbe and has no pre-made antibodies for defense. The immune system will eventually create antibodies for the microbe, but this is a slow process and, if the microbe is deadly, there may not be enough time for the antibodies to begin being used.
-Some major contemporary research in vaccination focuses on development of vaccinations for diseases including [[HIV vaccine|HIV]] and [[malaria]].
-''Vaccine'' is an international [[peer-reviewed]] journal for vaccination researchers, indexed in [[Medline]] pISSN: 0264-410X.
+Artificial active immunization is where the microbe is injected into the person before they are able to take it in naturally. The microbe is treated, so that it will not harm the injected person. Depending on the type of disease, this technique also works with dead microbes, parts of the microbe, or treated toxins from the microbe.
 ==See also==
+*[[Flu vaccine]]
+*[[H5N1 clinical trials|H5N1 flu vaccine clinical trials]]
 *[[Vaccine controversy]]
+*[[Expanded Program on Immunization (Philippines)]]
-==References==
+==External Links==
-<references/>
+* [http://www.immunizationinfo.org National Network for Immunization Information (NNii)]
+* [http://www.cdc.gov/nip Centers for Disease Control National Immunization Program ]
-==External links==
+{{Vaccines}}
-* [http://vaccines.org/ aggregation site] links to resources in many countries.  Growing.
-===Sites promoting vaccination policies===
-* [http://briandeer.com/mmr-lancet.htm Brian Deer.com] - 'mmr &  autism investigation: part 1: the ''Lancet'' scandal', [[Brian Deer]]
-* [http://www.cdc.gov/nip CDC.gov] - 'National Immunization Program: leading the way to healthy lives', [[Centers for Disease Control|US Centers for Disease Control]] (CDC information on vaccinations)
-* [http://www.cdc.gov/nip/vacsafe/concerns/thimerosal/default.htm CDC.gov]  - 'Mercury and Vaccines (Thimerosal)', US Centers for Disease Control
-* [http://www.immunize.org/ Immunize.org] - Immunization Action Coalition' (nonprofit working to increase immunization rates)
-* [http://nytimes.com/2005/06/25/science/25autism.html NYTimes.com] - 'On Autism's Cause, It's Parents vs. Research', Gardiner Harris, Anahad O'Connor, ''New York Times'' (front page; June 25, 2005)
-* [http://www.opinionjournal.com/editorial/feature.html?id=110004700 OpinionJournal.com] - 'Autism and vaccines: Activists wage a nasty campaign to silence scientists' (unsigned editorial opinion), ''[[Wall Street Journal]]'' (February 16, 2004)
-* [http://www.shns.com/shns/g_index2.cfm?action=detail&pk=FUMENTO-03-11-04 SNHS.com] - 'Anti-vaccine activists get jabbed', Michael Fumento (March 11, 2004)
-* [http://www.who.int/vaccines/ WHO.int] - 'Immunizations, vaccines and biologicals: Towards a World free of Vaccine Preventable Diseases', [[World Health Organization]] (WHO's global vaccination campaign website)
-===Sites critical of vaccination policies===
-* [http://www.909shot.com/ 909Shot.com] - 'National Vaccine Information Center: the oldest and largest national organization advocating reformation of the mass vaccination system'
-* [http://autism.about.com/cs/autisminprint/a/wakefieldfired.htm About.com] - "Killing the Messenger: Dr. Andrew Wakefield Fired", Floyd Tilton (December 5, 2001)
-* [http://www.vaccinationdebate.com/ VaccinationDebate.com] - 'Vaccination Debate', Ian Sinclair - despite the site's name, the author is unequivocally opposed to the science of vaccination.
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