Vaccination 2
A vaccine is a biological preparation that provides active acquired immunity to a particular infectious or malignant disease.[1] The safety and effectiveness of vaccines has been widely studied and verified.[2][3] A vaccine typically contains an agent that resembles a disease-causing microorganism and is often made from weakened or killed forms of the microbe, its toxins, or one of its surface proteins. The agent stimulates the body's immune system to recognize the agent as a threat, destroy it, and to further recognize and destroy any of the microorganisms associated with that agent that it may encounter in the future.
Vaccines can be prophylactic (to prevent or ameliorate the effects of a future infection by a natural or "wild" pathogen), or therapeutic (to fight a disease that has already occurred, such as cancer).[4][5][6][7] Some vaccines offer full sterilizing immunity, in which infection is prevented completely.[8]
The administration of vaccines is called vaccination. Vaccination is the most effective method of preventing infectious diseases;[9] widespread immunity due to vaccination is largely responsible for the worldwide eradication of smallpox and the restriction of diseases such as polio, measles, and tetanus from much of the world. The World Health Organization (WHO) reports that licensed vaccines are currently available for twenty-five different preventable infections.[10]
The folk practice of inoculation against smallpox was brought from Turkey to Britain in 1721 by Lady Mary Wortley Montagu.[11] The terms vaccine and vaccination are derived from Variolae vaccinae (smallpox of the cow), the term devised by Edward Jenner (who both developed the concept of vaccines and created the first vaccine) to denote cowpox. He used the phrase in 1798 for the long title of his Inquiry into the Variolae vaccinae Known as the Cow Pox, in which he described the protective effect of cowpox against smallpox.[12] In 1881, to honor Jenner, Louis Pasteur proposed that the terms should be extended to cover the new protective inoculations then being developed.[13] The science of vaccine development and production is termed vaccinology.
Infectious diseases before and after a vaccine was introduced. Vaccinations have a direct effect on the diminishment of the number of cases and contributes indirectly to a diminishment of the number of deaths.
Effects
A child with measles, a vaccine-preventable disease[14]
There is overwhelming scientific consensus that vaccines are a very safe and effective way to fight and eradicate infectious diseases.[15][16][17][18] The immune system recognizes vaccine agents as foreign, destroys them, and "remembers" them. When the virulent version of an agent is encountered, the body recognizes the protein coat on the agent, and thus is prepared to respond, by first neutralizing the target agent before it can enter cells, and secondly by recognizing and destroying infected cells before that agent can multiply to vast numbers.[19][20]
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History
Comparison of smallpox (left) and cowpox inoculations sixteen days after administration (1802)
Prior to the introduction of vaccination with material from cases of cowpox (heterotypic immunisation), smallpox could be prevented by deliberate variolation with smallpox virus. The earliest hints of the practice of variolation for smallpox in China come during the tenth century.[149]
The Chinese also practiced the oldest documented use of variolation, dating back to the fifteenth century. They implemented a method of "nasal insufflation" administered by blowing powdered smallpox material, usually scabs, up the nostrils. Various insufflation techniques have been recorded throughout the sixteenth and seventeenth centuries within China.[150]: 60 Two reports on the Chinese practice of inoculation were received by the Royal Society in London in 1700; one by Martin Lister who received a report by an employee of the East India Company stationed in China and another by Clopton Havers.[151]
An early 19th-century satire of antivaxxers by Isaac Cruikshank
Mary Wortley Montagu, who had witnessed variolation in Turkey, had her four-year-old daughter variolated in the presence of physicians of the Royal Court in 1721 upon her return to England.[150] Later on that year, Charles Maitland conducted an experimental variolation of six prisoners in Newgate Prison in London.[152] The experiment was a success, and soon variolation was drawing attention from the royal family, who helped promote the procedure. However, in 1783, several days after Prince Octavius of Great Britain was inoculated, he died.[153]
In 1796, the physician Edward Jenner took pus from the hand of a milkmaid with cowpox, scratched it into the arm of an 8-year-old boy, James Phipps, and six weeks later variolated the boy with smallpox, afterwards observing that he did not catch smallpox.[154][155] Jenner extended his studies and, in 1798, reported that his vaccine was safe in children and adults, and could be transferred from arm-to-arm, which reduced reliance on uncertain supplies from infected cows.[153] In 1804, the Spanish Balmis smallpox vaccination expedition to Spain's colonies Mexico and Philippines used the arm-to-arm transport method to get around the fact the vaccine survived for only 12 days in vitro. They used cowpox.[156] Since vaccination with cowpox was much safer than smallpox inoculation,[157] the latter, though still widely practiced in England, was banned in 1840.[158]
French print in 1896 marking the centenary of Jenner's vaccine
Following on from Jenner's work, the second generation of vaccines was introduced in the 1880s by Louis Pasteur who developed vaccines for chicken cholera and anthrax,[13] and from the late nineteenth century vaccines were considered a matter of national prestige. National vaccination policies were adopted and compulsory vaccination laws were passed.[154]
In 1931 Alice Miles Woodruff and Ernest Goodpasture documented that the fowlpox virus could be grown in embryonated chicken egg. Soon scientists began cultivating other viruses in eggs. Eggs were used for virus propagation in the development of a yellow fever vaccine in 1935 and an influenza vaccine in 1945. In 1959 growth media and cell culture replaced eggs as the standard method of virus propagation for vaccines.[159]
Vaccinology flourished in the twentieth century, which saw the introduction of several successful vaccines, including those against diphtheria, measles, mumps, and rubella. Major achievements included the development of the polio vaccine in the 1950s and the eradication of smallpox during the 1960s and 1970s. Maurice Hilleman was the most prolific of the developers of the vaccines in the twentieth century. As vaccines became more common, many people began taking them for granted. However, vaccines remain elusive for many important diseases, including herpes simplex, malaria, gonorrhea, and HIV.[154][160]
Generations of vaccines
First generation vaccines are whole-organism vaccines – either live and weakened, or killed forms.[161] Live, attenuated vaccines, such as smallpox and polio vaccines, are able to induce killer T-cell (TC or CTL) responses, helper T-cell (TH) responses and antibody immunity. However, attenuated forms of a pathogen can convert to a dangerous form and may cause disease in immunocompromised vaccine recipients (such as those with AIDS). While killed vaccines do not have this risk, they cannot generate specific killer T cell responses and may not work at all for some diseases.[161]
Second generation vaccines were developed to reduce the risks from live vaccines. These are subunit vaccines, consisting of specific protein antigens (such as tetanus or diphtheria toxoid) or recombinant protein components (such as the hepatitis B surface antigen). They can generate TH and antibody responses, but not killer T cell responses.[citation needed]
**RNA vaccines and DNA vaccines are examples of third generation vaccines.[161][162][163] In 2016 a DNA vaccine for the Zika virus began testing at the National Institutes of Health. Separately, Inovio Pharmaceuticals and GeneOne Life Science began tests of a different DNA vaccine against Zika in Miami. Manufacturing the vaccines in volume was unsolved as of 2016.[164] Clinical trials for DNA vaccines to prevent HIV are underway.[165] mRNA vaccines such as BNT162b2 were developed in the year 2020 with the help of Operation Warp Speed and massively deployed to combat the [COVID-19 pandemic](https://en.wikipedia.org/wiki/COVID-19_pandemic "COVID-19 pandemic"). In 2021, Katalin Karikó and Drew Weissman received Columbia University's Horwitz Prize for their pioneering research in mRNA vaccine technology.[166]
Wikipedia
Knowledge Web Content (see main node)
NAME: Vaccination
ALTERNATIVE NAME/S:
DETAILS/DESCRIPTION:
Vaccination (from Latin ‘vaca’ = cow) is the process of injecting particles of a virus which have been grown in a culture and then killed by heat or formaldehyde. Once injected, the vaccine causes the patient’s immune system to react in order to protect the patient. Some vaccines require regular boosters to reinforce this immune response.
Vaccination is so-called because in 1796 Dr Edward < introduced by> Jenner* used pus from relatively harmless cowpox as the vaccine against the deadly relative of the disease: smallpox. Jenner got the idea from Lady Mary Wortley Montagu* who, in Istambul in 1718, had seen Turks innoculate their children with the live cowpox virus. She had her own children innoculated and returned to England to spread the word.
After Jenner’s early experiments (preceded a decade before by the since-forgotten Benjamin Jesty), Pasteur* took up the work, growing the first first vaccine for rabies in rabbits. It was Pasteur who coined the term ‘vaccination.’
ONELINER: Vaccination
OTHER CONNECTIONS: None
BIBLIOGRAPHY:
Encyclopaedia Britannica