1 Smallpox and the history of vaccination
1.1 The smallpox virus
Undoubtedly, one of the great success stories of modern medicine has been in the field of vaccination against infectious diseases. There is no more compelling example than smallpox. It is hard now to imagine the impact of smallpox, which killed 10–50% (sometimes more) of the people it infected and wiped out whole communities. In the nineteenth century, the English parliamentary historian Thomas Macaulay graphically described its effects:
Smallpox was always present, filling the churchyard with corpses, tormenting with constant fear all whom it had not yet stricken, leaving on those whose lives it spared the hideous traces of its power, turning the babe into a changeling at which the mother shuddered, and making the eyes and cheeks of the betrothed maiden objects of horror to the lover.
(From The History of England from the Accession of James II by Thomas Macaulay, completed 1855)
Smallpox, caused by the variola virus, is thought to have originated in the first agricultural settlements in North Africa and was one of the greatest scourges of humanity for at least 10000 years. It holds a special place in the history of immunology and infectious disease as the first disease for which an effective vaccine was developed and the first to be eradicated globally (confirmed by the WHO in 1980).