Jenner, Edward WORLD OF MICROBIOLOGY AND IMMUNOLOGY320•
smallpox pustule induced a mild case of the disease and subse-
quent immunity. This practice of inoculation, termed variola-
tion, reached England by the eighteenth century. However, it
was quite risky as those who were inoculated frequently suf-
fered a severe or fatal case of smallpox. Despite the risk, peo-
ple willingly agreed to inoculation because of the widespread
incidence of smallpox and the fear of suffering from terribly
disfiguring pockmarks that resulted from the disease.
As a young physician, Jenner noted that dairy workers
who had been exposed to cowpox, a disease like smallpox
only milder, seemed immune to the more severe infection. He
continually put forth his theory that cowpox could be used to
prevent smallpox, but his contemporaries shunned his ideas.
They maintained that they had seen smallpox victims who
claimed to have had earlier cases of cowpox.
It became Jenner’s task to transform a country supersti-
tion into an accepted medical practice. For up until the mid –
1770s, the only documented cases of vaccinations using cow-
pox came from farmers such as Benjamin Jesty of Dorsetshire
who vaccinated his family with cowpox using a darning needle.
After observing cases of cowpox and smallpox for a
quarter century, Jenner took a step that could have branded
him a criminal as easily as a hero. On May 14, 1796, he
removed the fluid from a cowpox lesion from dairymaid SarahNelmes, and inoculated James Phipps, an eight-year-old boy,
who soon came down with cowpox. Six weeks later, he inoc-
ulated the boy with smallpox. The boy remained healthy.
Jenner had proved his theory. He called his method vaccina-
tion, using the Latin word vacca,meaning cow, and vaccinia,
meaning cowpox. He also introduced the word virus.
The publication of Jenner’s An Inquiry into the Causes
and Effects of the Variolae Vaccinaeset off an enthusiastic
demand for vaccination throughout Europe. Within 18
months, the number of deaths from smallpox had dropped by
two-thirds in England after 12,000 people were vaccinated. By
1800, over 100,000 people had been vaccinated worldwide. As
the demand for the vaccinerapidly increased, Jenner discov-
ered that he could take lymph from a smallpox pustule and dry
it in a glass tube for use up to three months later. The vaccine
could then be transported.
Jenner was honored and respected throughout Europe
and the United States. At his request, Napoleon released sev-
eral Englishmen who had been jailed in France in 1804, while
France and Great Britain were at war. Across the Atlantic
Ocean, Thomas Jefferson received the vaccine from Jenner
and proceeded to vaccinate his family and neighbors at
Monticello. However, in his native England, Jenner’s medical
colleagues refused to allow him entry into the College ofEdward Jenner (right), innoculating a boy with cowpox virus as a protection against smallpox.womi_J 5/6/03 3:28 PM Page 320