Vaccines in Our Lifetime
The Vaccine Effect
How Science Conquered the World’ s Deadliest Diseases
Jane Thrall
Vaccines have been protecting the public against some of the world’ s most devastating diseases, saving lives, and preventing the spread of illness on a global scale.
Jane Thrall is a staunch supporter of science, research, and objective evidence. As a former researcher in chemistry and neuroscience, and a long-time healthcare provider, she enjoys reading about and researching new scientific discoveries.
The World Health Organization estimates that over the last half-century alone, immunization has prevented the deaths of at least 154 million people, mostly infants.
In 1796 with smallpox ravaging the country, English physician Edward Jenner noted that people who had previously contracted the far milder cowpox were less likely to succumb to the more virulent smallpox. He began treating his patients with a dose of cowpox, hoping it would provide immunity to smallpox, in effect creating the first vaccine and establishing the field of immunology.
In the late 1800s, Louis Pasteur developed the first vaccines using attenuated pathogens. He found that exposing microbes to heat caused them to lose much of their potency. Using these weakened bacteria, he vaccinated chickens for fowl cholera, sheep and cattle for anthrax, and pigs for swine erysipelas. These disabled pathogens triggered an immune reaction, effectively priming the animal’ s defences against a subsequent exposure to the disease.
Pasteur also successfully treated post-exposure rabies by providing a patient with a series of injections of labproduced virus in increasing potency. This graduated exposure stimulated the production of antibodies, saving the patient’ s life.
Following the Second World War, polio outbreaks were frequent and widespread. Highly contagious, polio left many of its victims with permanent muscle and nerve damage. Children were particularly at risk: one in every two hundred infections resulted in often fatal paralysis. Little could be done to prevent spread, short of isolating
Vaccines in Our Lifetime
1963
Measles vaccine introduced
1980
Smallpox eliminated worldwide
1994
Polio declared eliminated in Canada
1955
Polio vaccine introduced
24 | arta. net STAY HEALTHY
1971
Combined MMR( Measles, Mumps, Rubella) vaccine becomes available
1986
Hepatitis B vaccine introduced