Vaccination - Wikipediapio on of antigenic material (a vaccine) to stimulate an individual's immune system to develop adaptiveimmunity to a pathogen. Vaccines can prevent or ameliorate morbidity from infection. When a sufficiently large percentage of a population has been vaccinated, this results in herd immunity. The effectiveness of vaccination has been widely studied and verified; for example, the influenza vaccine. The World Health Organization (WHO) reports that licensed vaccines are currently available to prevent or contribute to the prevention and control of twenty- five preventable infections. Toxoids are produced for immunization against toxin- based diseases, such as the modification of tetanospasmin toxin of tetanus to remove its toxic effect but retain its immunogenic effect. The smallpox vaccine was discovered in 1. British physician Edward Jenner, although at least six people had used the same principles years earlier. The immunization was called vaccination because it was derived from a virus affecting cows (Latin: vacca. This distinguishes it from inoculation, which uses unweakened live pathogens, although in common usage either can refer to an immunization. Vaccination efforts have been met with some controversy on scientific, ethical, political, medical safety, and religious grounds. In rare cases, vaccinations can injure people and, in the United States, they may receive compensation for those injuries under the National Vaccine Injury Compensation Program. Early success and compulsion brought widespread acceptance, and mass vaccination campaigns have greatly reduced the incidence of many diseases in numerous geographic regions. Mechanism of function. Stimulating immune responses with an infectious agent is known as immunization. The Costs of Vaccine Damage: The Payout Figures. Statement on National Vaccine Injury Compensation Program by Thomas E. Director, National Vaccine Injury Compensation Program. Vaccination includes various ways of administering immunogens. Some vaccines are administered after the patient already has contracted a disease. Vaccines given after exposure to smallpox, within the first three days, are reported to attenuate the disease considerably, and vaccination up to a week after exposure probably offers some protection from disease or may modify the severity of disease. Subsequent to this, it has been found that, in people with uncompromised immune systems, four doses of rabies vaccine over 1. Such immunizations aim to trigger an immune response more rapidly and with less harm than natural infection. Most vaccines are given by hypodermic injection as they are not absorbed reliably through the intestines. Live attenuated polio, some typhoid, and some cholera vaccines are given orally to produce immunity in the bowel. While vaccination provides a lasting effect, it usually takes several weeks to develop, while passive immunity (the transfer of antibodies) has immediate effect. 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 1. Persian 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. Vaccines may also contain preservatives 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 2. 00. 5, the only childhood vaccine in the U. S. 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. In fact, they are different things. As doctor Byron Plant explains: . Inoculation, a practice probably as old as the disease itself, is the injection of the variola virus taken from a pustule or scab of a smallpox sufferer into the superficial layers of the skin, commonly on the upper arm of the subject. Often inoculation was done 'arm to arm' or less effectively 'scab to arm'.. Four main types are currently in clinical use: An inactivated vaccine consists of virus or bacteria that are grown in culture and then killed using a method such as heat or formaldehyde. Although the virus or bacteria particles are destroyed and cannot replicate, the virus capsid proteins or bacterial wall are intact enough to be recognized and remembered by the immune system and evoke a response. When manufactured correctly, the vaccine is not infectious, but improper inactivation can result in intact and infectious particles. Since the properly produced vaccine does not reproduce, booster shots are required periodically to reinforce the immune response. In an attenuated vaccine, live virus or bacteria with very low virulence are administered. They will replicate, but locally or very slowly. Since they do reproduce and continue to present antigen to the immune system beyond the initial vaccination, boosters may be required less often. These vaccines may be produced by passaging, for example, adapting a virus into different host cell cultures, such as in animals, or at suboptimal temperatures, allowing selection of less virulent strains, or by mutagenesis or targeted deletions in genes required for virulence. There is a small risk of reversion to virulence, which is smaller in vaccines with deletions. Attenuated vaccines also cannot be used by immunocompromised individuals. Reversions of virulence were described for a few attenuated viruses of chickens (infectious bursal disease virus, avian infectious bronchitis virus, avian infectious laryngotracheitis virus . These proteins can self- assemble into particles that resemble the virus from which they were derived but lack viral nucleic acid, meaning that they are not infectious. Because of their highly repetitive, multivalent structure, virus- like particles are typically more immunogenic than subunit vaccines (described below). The human papillomavirus and Hepatitis B virus vaccines are two virus- like particle- based vaccines currently in clinical use. A subunit vaccine presents an antigen to the immune system without introducing viral particles, whole or otherwise. One method of production involves isolation of a specific protein from a virus or bacterium (such as a bacterial toxin) and administering this by itself. A weakness of this technique is that isolated proteins may have a different three- dimensional structure than the protein in its normal context, and will induce antibodies that may not recognize the infectious organism. In addition, subunit vaccines often elicit weaker antibody responses than the other classes of vaccines. A number of other vaccine strategies are under experimental investigation. These include DNA vaccination and recombinant viral vectors. History. Smallpox used to be a common disease throughout the world and 2. Smallpox was responsible for 8 to 2. European countries in the 1. The tradition of vaccination may have originated in India in AD 1. This kind of inoculation and other forms of variolation were introduced into England by Lady Montagu, a famous English letter- writer and wife of the English ambassador at Istanbul between 1. Inoculation was adopted both in England and in America nearly half a century before Jenner's famous smallpox vaccine of 1. But it was Edward Jenner, a doctor in Berkeley, who established the procedure by introducing material from a cowpox vesicle on Sarah Nelmes, a milkmaid, into the arm of a boy named James Phipps. Two months later he inoculated the boy with smallpox and the disease did not develop. In 1. 79. 8, Jenner published . He distinguished 'true' and 'spurious' cowpox (which did not give the desired effect) and developed an . Early attempts at confirmation were confounded by contamination with smallpox, but despite controversy within the medical profession and religious opposition to the use of animal material, by 1. Vaccines are now used against a wide variety of diseases besides smallpox. Louis Pasteur further developed the technique during the 1. The method Pasteur used entailed treating the agents for those diseases so they lost the ability to infect, whereas inoculation was the hopeful selection of a less virulent form of the disease, and Jenner's vaccination entailed the substitution of a different and less dangerous disease for the one protected against. Pasteur adopted the name vaccine as a generic term in honor of Jenner's discovery. Maurice Hilleman was the most prolific vaccine inventor, and developed successful vaccines for measles, mumps, hepatitis A, hepatitis B, chickenpox, meningitis, pneumonia and Haemophilus influenzae. The World Health Organization (WHO) coordinated this global eradication effort. The last naturally occurring case of smallpox occurred in Somalia in 1. In 1. 98. 8, the governing body of WHO targeted polio for eradication by 2. Although the target was missed, eradication is very close. The next disease to be targeted for eradication would most likely be measles, which has declined since the introduction of measles vaccination in 1. GAVI is now entering its second phase of funding, which extends through 2. Society and culture. For example, an 1. England and Wales, with fines levied on people who did not comply. Common contemporary U. S. Common objections are that vaccinations do not work, that compulsory vaccination represents excessive government intervention in personal matters, or that the proposed vaccinations are not sufficiently safe. In Australia, for example, the Government subsidizes vaccinations for seniors and indigenous Australians. Even though the article was fraudulent and was retracted, 1 in 4 parents still believe vaccines can cause autism. These pathogens could possibly infect vaccinated people, due to the pathogen's ability to mutate when it is able to live in unvaccinated hosts.
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