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VaccinationVaccination is a term coined by Edward Jennerfor the process of administering live, albeit weakened, microbes to patients, with the intent of conferring immunity against a targeted form of a related disease agent. Vaccination (Latin: vacca—cow) is so named because the first vaccinewas derived from a virusaffecting cows: the cowpoxvirus, 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 initially met with some resistancebefore early success brought widespread acceptance and mass vaccination campaigns were undertaken. The eradication of smallpoxis considered the most spectacular success of vaccination. The last natural case of smallpox was discovered on October 261977in Somalia. This date is considered the anniversary of the eradication of smallpox. Some people assert that childhood vaccination plays a role in autoimmune diseaseand autism, though large-scale scientific studies have not shown any link.
Triggering immune sensitizationIn the generic sense, the process of triggering immune response, in an effort to protect against infectious disease, works by 'priming' the immune systemwith an 'immunogen'. Stimulating immune response, via use of an infectious agent, is known as 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, cancerand Alzheimer's diseasevaccines. Vaccinia given after exposure to smallpox, within the first four days, is reported to attenuate the disease considerably, as vaccination within the first week is thought to be beneficial to a degree. 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 in the form of 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 vaccinationsVaccination campaigns have spread throughout the globe since Jenner's smallpox vaccine of 1796, sometimes prescribed by law or regulations (See vaccination Acts ). Vaccines are now used to fight a wide variety of disease threats besides smallpox. Louis Pasteurfurther developed the technique during the 19th century, extending its use to protecting against bacterial anthraxand 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. Anti-vaccinationist Movements and Anti-vaccinationists. Various groups and individuals agitated against vaccination for individual and mass benefit, and this minority activity continues to the current time. Arguments from religious, scientific, emotional and assorted bases tend to persist and be broadcast regardless of their merit. Some but perhaps not a majority of those involved profit by promoting alternatives. See Anti-vaccinationists 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 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 Immunizations, www.vaccinealliance.org, was established to strengthen routine vaccinations and introduce new and under-used vaccines in countries with GDP of under US$1000. GAVI is now entring its second phase of funding, which extends through 2014. Herd immunity and medical risk management issuesVaccination campaigns are generally accepted as having contributed to the worldwide elimination of smallpox, through herd immunity, and to the restriction of polioto isolated pockets in countries where healthcare access is difficult. The risk managementpractices 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, measlesand rubella, are now relatively rare. Nevertheless, vaccination campaigns may have unfortunate co-evolutionaryside-effects, particularly if they produce a selective pressure in favor of certain strains against which there are no vaccines or 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 nichethat has been vacated. For example, it has been postulated that (the less-often-fatal) serogroup-B meningitisstrains 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. An incompletely-successful attempt at eradication of a disease through vaccination might increase the 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 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. Adjuvants and preservativesVaccines typically contain one or more adjuvants, used to boost the immune response. 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 Tet. Tox. People who gt an excessive reaction to adsorbed Tet Tox 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.
Peer-Reviewed JournalsVaccine is an international journal for original research and other papers, indexed in MedlinepISSN: 0264-410X. References^ Melinda Wharton. National Vaccine Advisory committee www.alertnet.org Sites promoting vaccination policies
Sites critical of vaccination policies
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