If we take a closer look at the history of vaccination we shall see that from the outset our vaccine legend appears to have been based on some historical manoeuvring designed to gloss over some inconvenient truths.
Cowpox was a mild skin disease believed to be contracted from skin contact with the microbes on the udders of cows, during the milking process, whereas smallpox was a dreaded disease manifesting unsightly pustules on the skin, was difficult to treat and with a high incidence of fatalities. The aftermath often affected the appearance of the skin, and could lead to chronic disorders and other adverse effects. Edward Jenner thought he had discovered the mechanism behind the porcelain beauty of milkmaids, having contracted cowpox they were then immune to smallpox and could never be defaced by this dreaded condition.
It was thought that the microbe responsible for cowpox was similar to the microbe responsible for smallpox. Therefore Jenner deduced that the human immune response to cowpox was also effective against smallpox. Having contracted cowpox an individual would be immune to future contact with smallpox; he therefore hypothesised that if he could get individuals to contract cowpox they would be protected against smallpox. On the face of it, a reasonable hypothesis and given the lack of clinical success at treating smallpox, it would appear to be a hypothesis well worth pursuing.
This would form the initial basis for the development of vaccination, however, it is worth noting at this point, that many doctors and members of the public rejected the idea of immunity to smallpox from natural cowpox, as they could testify to having cowpox and yet still contracted smallpox in later life.
Lily Loat writing extensively on the history of smallpox and vaccination states
“That cases of smallpox, of typhus, and of others of the ordinary epidemics, occur in the greatest proportion, in common conditions of foul air from stagnant putrefaction, from bad house drainage from sewers of deposit, from excrement-sodden sites, from filthy street surfaces, from impure water, and from overcrowding in private houses and in public institutions. That the entire removal of such conditions by complete sanitation and by improved dwellings is the effectual preventive of disease of these species, and of ordinary as well as extraordinary epidemic visitations”
“Smallpox, as well as typhus, takes up its abode most readily in those places where the noxious influences due to neglected hygiene make themselves most felt.”
“The tradition of the dairymaids as to the protection afforded by cowpox against smallpox was rejected by many of Jenner’s own medical acquaintances because they knew of numerous cases where those who had had cowpox subsequently developed smallpox.”