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Dr. Edward Jenner: Discovering
the Smallpox Vaccine
In light of current times, we thought you might be interested in
the history of the smallpox vaccine. While you may know that Dr.
Edward Jenner discovered and developed the smallpox vaccine, are
you aware that this discovery was more than 200 years ago? Dr. Jenner's
discovery eventually resulted in the World Health Organization's
official determination and pronouncement in 1980 that smallpox had
been eradicated-fulfilling Jenner's own prediction made in 1801.
Edward Jenner was born in 1749 and spent much of his adult life
as a country doctor in western England. In his lifetime, smallpox
was a dreaded endemic disease, particularly deadly among children.
Prior to the discovery of the smallpox vaccine, this devastating
disease accounted for 10 to 20 percent of deaths — killing
up to one-third of children — in towns and cities where infection
spread easily. Deeply concerned for the loss of lives, Dr. Jenner
became determined to find an effective method to protect people
from the disease. His hard work and innovative disease analysis
led to the creation of the smallpox vaccination. Dr. Jenner actually
invented the word "vaccination" for his treatment from
the Latin "vacca" for cow (as described further below).
The Disease
A very ancient disease, smallpox is caused by the virus variola.
The mode of infection is through the lungs. Once in the blood stream,
the virus infects internal organs. The virus spreads to the skin
where it multiples, causing the characteristic rash and pocks, which
often leaves victims scarred by the severity of the blistering.
For possibly thousands of years, smallpox took its toll in all parts
of the world. Smallpox spread throughout Europe and was carried
to the Americas by explorers and settlers. We know of the unfortunate
devastation of many cultures from smallpox including the Aztecs.
In North America, more Indians died of smallpox than in battles
with white settlers.
Many attempts were made to inoculate individuals from smallpox.
One such attempt which met with marginal success was the practice
of variolation which was an attempt to reduce the likelihood of
death from smallpox by scratching into your skin a bit of the scab
material from someone with a mild form of the disease. The idea
behind variolation has vague similarities to vaccination (although
that word had yet to be created), that being the inoculation of
an uninfected individual with a form or fragment of the organism
causing the disease to build up the immune system against that disease.
The problem with variolation was the imprecise identification of
a suitable strain and the rather horrific methodology associated
with the practice. Needless to say, many died from the practice
of variolation.
Jenner's Observations and Experiments
As a country doctor and astute observer, Jenner had the opportunity
to see and treat many people who contracted cowpox, a mild viral
infection of cows. Milkmaids would occasionally catch cowpox as
a result of their employ. They would feel a bit out of sorts for
a few days, develop a few minor pocks usually at the point of contact
with the cowpox (their hands), but otherwise were fine within a
few days. These individuals then seemed immune from smallpox. This
observation and Jenner's clear understanding of the risks associated
with variolation prompted him to undertake a careful scientific
study-observation and analysis of possible preventative treatments
for smallpox. Remember that Jenner embarked on this endeavor far
before the smallpox virus was understood nor methods existed to
do the same.
In May 1796, one of Jenner's patients, Sarah Nelmes, complained
of a rash on her hand. He diagnosed cowpox rather than smallpox,
and Sarah confirmed that one of her cows had recently had cowpox.
Jenner took this presentment of cowpox as an opportunity to test
the protective properties of cowpox by giving it to someone who
had not yet suffered smallpox. He chose James Phipps, the eight-year-old
son of his gardener. Jenner made a few scratches on one of James'
arms and then rubbed some material from one of the Sarah's pocks
into the openings. A few days later James became mildly ill with
cowpox but was well again a week later. So Jenner knew that cowpox
could pass from person to person as well as from cow to person.
The next step was to test whether the cowpox would now protect James
from smallpox. To test his theory, approximately two months later,
Jenner variolated the boy. To Jenner's delight, James did not develop
smallpox, either on this occasion or at any other time when others
in James' village succumbed to smallpox.
Jenner repeated his experiment of skin inoculating previously uninfected
and non-variolated individuals with cowpox with the same success.
He published the results in 1798 in a book entitled An Inquiry
into the Causes and Effects of the Variolae Vaccinae; a Disease
Discovered in some of the Western Counties of England, Particularly
Gloucestershire, and Known by the Name of The Cow Pox. In each
of the next two years he published the results of further experiments,
which confirmed his original theory.
Compulsory Vaccination
As a result of Jenner's discovery and continued experiments which
proved that cowpox did indeed protect against smallpox, many countries
began to require compulsory vaccination including countries such
as Bavaria (1807), Denmark (1810) and Prussia (1835). Despite Jenner
being English, Britain took until 1853 to make vaccination against
smallpox a matter of law. This practice became widespread throughout
Europe, but outbreaks continued as a result of unsuspecting travelers
from countries without the vaccination system and where smallpox
still existed as an endemic disease.
The World Health Organization (WHO) realized the only means by
which to truly eradicate smallpox was to initiate a worldwide vaccination
campaign. Launched in 1967, WHO effectively vaccinated the world
population through dispatching scores of vaccinating teams to every
corner of the world. The last known case of smallpox was in Somalia
in 1977. Ali Maow Maalim, a Somali hospital worker was the last
person on earth to catch smallpox by natural transmission. Upon
notification of this case, WHO dispatched to Maalim's home, a medical
team which literally camped on his doorsteps until Maalim was no
longer infectious. WHO anxiously waited another three years, watching
for any new cases before announcing in 1980 the worldwide eradication
of smallpox and the first major infectious disease to be removed
from the face of the earth.
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