Inoculation

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Inoculation, originally Variolation, is a method of purposefully infecting a person with smallpox (Variola) in a controlled manner so as to minimise the severity of the infection and also to induce immunity against further infection. It preceded vaccination and is separate from it, though today the terms inoculation, vaccination and immunisation are used more or less interchangeably and popularly refer to the process of artificial induction of immunity against various infectious diseases. The microorganism used in an inoculation is called the inoculant or inoculum.

Typical site of inoculation in Europe and the British colonies

Inoculation in the East was historically performed by blowing smallpox crusts into the nostril, but in Britain, Europe and the American Colonies the preferred method was rubbing material from a smallpox pustule from a selected mild case - Variola Minor - into a scratch between the thumb and forefinger. [3] This would generally be performed when an individual was in normal good health, and thus at his peak resistance. The recipient would develop smallpox; however, due to being introduced through the skin rather than the lungs, and possibly because of the inoculated individual's preexisting state of good health, the small inoculum, and the single point of initial infection, the resulting case of smallpox was generally milder than the naturally-occurring form, produced far less facial scarring, and had a far lower mortality rate. As with survivors of the natural disease, the inoculated individual was subsequently immune to re-infection.

1 Origins and Importation to Christendom
2 Mechanism
3 Supplanted by vaccination
4 See also
5 References

[edit] Origins and Importation to Christendom

Mary Wortley Montagu, by Charles Jervas, after 1716.

The earliest use of inoculation is unknown. It had been widely practised in India, the Ottoman Empire, and east Africa. The practice was introduced to the west by Lady Mary Wortley Montagu (May 26, 1689-August 21, 1762). Lady Montagu's husband, Edward Wortley Montagu, served as the British ambassador to the Ottoman Empire from 1716 to 1717. She witnessed inoculation in Constantinople, and was greatly impressed: she had lost a brother to smallpox and bore facial scars from the disease herself. In March 1718 she had the embassy surgeon, Charles Maitland, inoculate her five-year-old son. In 1721, after returning to England, she had her four-year-old daughter inoculated. She invited friends to see her daughter, including Sir Hans Sloane, the King's physician. Sufficient interest arose that Maitland gained permission to test inoculation at Newgate prison in exchange for their freedom on six prisoners due to be hanged, an experiment which was witnessed by a number of notable doctors. The experiment succeeded, and in 1722 the Prince of Wales' daughters received inoculations.

The practice of inoculation slowly spread amongst the royal families of Europe, usually followed by more general adoption amongst the people.

The practice is documented in America as early as 1721. Cotton Mather in Boston had a description of the African practice of inoculation from his slave Onesimus and encouraged its application, with considerable controversy and strife. Fearing the outbreak of an epidemic, the editor of the South Carolina Gazette published a detailed description of the inoculation process in the April 22 issue. In Boston, there was opposition from churchmen regarding the practice who regarded it as "bidding defiance to Heaven itself, even to the will of God", though one historian also notes that "...within a year or two after the first experiment nearly three hundred persons had been inoculated ... in Boston and neighbouring towns, and out of these only six had died; whereas, during the same period, out of nearly six thousand persons who had taken smallpox naturally, and had received only the usual medical treatment, nearly one thousand had died." (from A History Of The Warfare Of Science With Theology In Christendom by Andrew Dickson White.)

Natural experiment in Inoculation around Boston, 1721
	Total	Died	Mortality %
Variolated	c 300	6	c 2%
Unvariolated	c 6000	c 1000	"about 14%"

(The 14% figure rather than 17% comes from
"Edward Jenner and Vaccination." Harris[4])

J.Z. Holwell described the Ayurvedic system of inoculation against smallpox to the Royal College of Physicians in London in 1767^[1] . He based his account on observations made during his residence in Bengal.

In France considerable opposition arose to the introduction of inoculation. Voltaire, in his Lettres Philosophiques, wrote a criticism of his countrymen for being opposed to inoculation and having so little regard for the welfare of their children, concluding that "had inoculation been practised in France it would have saved the lives of thousands." ^[2].

Inoculation grew in popularity in Europe through the 18th century. Given the high prevalence and often severe consequences of smallpox in Europe in the 18th century (according to Voltaire, there was a 60% incidence of first infection, a 20% mortality rate, and a 20% incidence of severe scarring),^[3] many parents felt that the benefits of inoculation outweighted the risks and so inoculated their children^[4].

[edit] Mechanism

Two forms of the disease of Smallpox were recognised, now known to be due to two strains of the Variola virus. Those contracting Variola Minor had a greatly reduced risk of death - 1-2% - compared to those contracting Variola Major with 20% mortality. Infection via the lungs - inhaled viral particles in droplets - spread the infection more widely than the deliberate infection through a small skin wound. The smaller, localised infection is adequate to stimulate the immune system to produce specific immmunity to the virus, while requiring more generations of the virus to reach levels of infection likely to kill the patient. The rising immunity terminates the infection. So the twofold effect is to ensure the less fatal form of the disease is the one caught, and to give the immune system the best start possible in combating it.

[edit] Supplanted by vaccination

Main article: Vaccination

In 1796, Edward Jenner introduced the far safer method of inoculation with the cowpox virus, a non-fatal virus that also induced immunity to smallpox. This led to smallpox inoculation falling into disuse and eventually being banned in England in 1840.

[edit] See also

[edit] References

^ An account of the manner of inoculating for the small pox in the East Indies. John Zephaniah Holwell. 1767
^ Lettres Philosophiques. Voltaire. (English translation on-line [1])
^ In fact, the mortality rate of the Varoiola Minor form of smallpox then found in Europe was 1-3% as opposed to 30-50% for the Variola Major type found elsewhere; however. blindness, infertility, and severe scarring were common. Figures from "The Search for Immunisation", In Our Time, BBC Radio 4 (2006). [2]
^ Letter of Lady Montagu reproduced at http://www.foundersofscience.net/lady_mary_montagu.htm viewed 18 March 2006