unchsl:

Letter from Doctor Edward Jenner, to William Dillwyn, Esq., on the effects of vaccination… (1818, located in the UNC HSL Special Collections) details the ways in which the smallpox vaccine (debuted by Edward Jenner in 1798) helped to stop the spread of smallpox in various countries. 
Though Jenner compares smallpox to a “ghost” that takes “…an annual stalk over the country” (Jenner, 6), Jenner’s results show how powerful his vaccinations were (even against such a sinister opponent).  By Jenner’s own estimate, in the first 20 years after the advent of vaccination, deaths from smallpox were “…reduced from more than 40,000 to less than 6,000″ (Jenner, 4).  For as he states:

Wherever Vaccination has been universally practiced, there the small-pox ceases to exist.  It matters not how wide the district or how populous the city, the result is, and, from the nature of things, must be the same.

(Jenner, 1)

Indeed, Jenner’s persuasive prose is as effective as the vaccine itself in stopping the protests of his naysayers.  Dynamically worded and passionate, Jenner’s letter is a must-read for anyone studying the development of modern vaccines.