VACCINATION
Immunization is in preventive
medicine process of rendering people immune to an infectious organism by 
inoculating them with a form of the
organism that doesn’t cause severe disease, but does provoke formation of
protective antibodies. The process has also been called vaccination, because
the first instance of immunization was the use of vaccinia
or cowpox, virus to produce immunity to variola or
smallpox. Vaccines are the most effective protection against most diseases
caused by viruses and related organisms, because few antibiotics work against
them. In Western countries vaccines are routinely used in the first years of
life to produce immunity to diptheria, tetanus,
poliomyelitis, Haemophilus influenza type B and
whooping cough.
A vaccine may contain: organisms
killed by exposure to heat or chemicals (the first polio vaccine, and one for
typhoid fever); an inactivated form of a toxin, produced by the organism and
called a toxoid (tetanus and diphtheria vaccines); or
a live “attenuated” virus—one grown in such a way that it can no longer cause
serious disease (the polio vaccine developed by Albert Sabin
and vaccines against measles and yellow fever).
The first modern use of immunization
was by the British doctor Edward Jenner
in 1796, when he used cowpox inoculations to produce protection against
smallpox. In 1885 the French scientist Louis
Pasteur first used an attenuated rabies virus to protect against the
natural infection and in 1897 a vaccine against typhoid fever was developed in
The immunizing substance is usually
introduced through a scrape in the skin, called inoculation, although the Sabin polio
vaccine is taken orally. Protection lasts for varying periods: the plague
vaccine for only six months; the yellow fever vaccine for ten years.
A population can be immunized in two
ways. In one method, the vaccine is targeted at those most likely to get the
disease. In the recent successful campaign to eradicate smallpox worldwide, a
form of this strategy was used. Most diseases in Western countries, on the
other hand, are controlled through the principle of herd immunity, in which it
is held that the transmission of disease will be stopped when an extremely low
probability exists that an infected person will come into contact with an
unprotected individual. Not every person needs to be immunized, but protection
levels of 90 per cent must be reached for some diseases. In some instances a
combined strategy is used. For rubella, or German measles, for example, public
health workers aim at mass immunization of school-age children as well as of
women of childbearing age.
New vaccines are still being
developed, such as a safer, less
painful vaccine against rabies and
vaccines against hepatitis B and pneumonia-causing bacteria. Diseases common in
the developing world for which vaccines are being sought include cholera and
parasitic infections such as malaria and trypanosomiasis
(sleeping sickness). In addition to active immunization (stimulating antibody
formation by introducing a form of the infectious organism), protection may
also be provided by passive immunization (injecting serum containing
antibodies, usually obtained from a person who has recently had the disease).
The latter procedure is now seldom used, except in some cases of hepatitis.
Rudolf
Weigl 1883 – 1957 Thomas
Weller 1915 – “ Now
protect with vaccination against influenza ! ”
discovered Typhus vaccination discovered Rubella vaccination German slogan
Edward Jenner 1749 – 1823
British doctor,
who discovered the vaccine that is used against smallpox and who laid the groundwork for 
the science of
immunology. Born
on 
rural vicarage, Jenner became a keen
observer of nature at an early age. After nine years as a surgeon's apprentice,
he went to
Smallpox, a
major cause of death in the 18th century, was treated in Jenner's
time by the often-fatal procedure of inoculating healthy persons with pustule
substances from those who had mild cases of 
the disease. Jenner observed, among
his patients, that those who had been exposed to the much milder disease cowpox
were completely resistant to these inoculations. In 1796 he inoculated an
eight-year-old boy with cowpox virus; six weeks after the boy's reaction Jenner
reinoculated him with smallpox virus, finding the
result negative. By 1798, having added similarly successful cases, Jenner wrote
An Inquiry into the Causes and Effects of the Variolae Vaccinae, a Disease Known by the
Name of Cow Pox, a tract in which he also introduced the term virus.
Jenner encountered some public
resistance and professional chicanery in publicizing his findings, and he
experienced difficulties in obtaining and 
preserving cowpox vaccine.
Nevertheless, his procedure was soon accepted, and mortality due to smallpox
plunged. The procedure quickly spread through
Jonas Edward salk 1914 – 1995
American doctor and epidemiologist,
who developed the first vaccine against poliomyelitis. Salk's work in the 1940’s on an antiinfluenza vaccine led him and his colleagues to develop
an inactivated vaccine against polio
in 1952. After successful wide-scale testing in 1954, the vaccine was
distributed nationally and greatly reduced the disease. In the mid-1950’s the
American virologist Albert Sabin developed an attenuated (live) oral vaccine,
which with Salk's discovery brought polio under control
Albert Bruce sabin 1906 – 1993
Polish-born
American virologist, who developed an oral, live-virus poliomyelitis vaccine. Born in
