Vaccines are ‘miracle’ medications that have saved millions of human lives in the short history of its usage. At different stages in modern history, vaccines have addressed various diseases. For example, hundred years ago it was employed to control diphtheria in young children. Half a century back, polio was the greatest scare for children, and vaccines helped limit it’s occurrence. As a result of vaccines, most serious threats to childhood mortality and disability have been eliminated. A recent success is the eradication of smallpox in 1980. It is fair to say that vaccines have saved more human lives than any other modern medical intervention: “Viruses cause annoyances like the common cold, but they can also kill: Diphtheria, for instance, kills one tenth of those who contract it. Tetanus kills one third.” (Izakson)
Before vaccines were invented, people depended on the body’s natural immunity to fight infections. It is a time tested truth that an individual, once infected with a disease, after having recovered from it is unlikely to catch it again. This is so because during the primary infection, the immune system develops necessary counteracting components for fighting intruding micro-organisms. This system remains intact and springs into action when the infection attempts to enter the person second time around. This method was even applied systematically in China in the 17th century. Called ‘variolation’, it was tried successfully in preventing smallpox.
“A small amount of a patient’s smallpox scab was rubbed into the skin of uninfected individuals, inducing a mild form of the disease followed by protective immunity. Although around 1-2 percent of variolated people contracted the disease and died, the odds were still favourable during a raging epidemic. In 1796, Edward Jenner took note of the folk observation that milkmaids had creamy complexions: they did not get smallpox. Jenner successfully used the relatively harmless cowpox as a vaccine (from the Latin vacca, “cow”) in place of smallpox.” (Weiss and Hale)
The mechanism through which vaccines operate is by activating the body’s natural defences so that it prevents infection. Not only are vaccines used by human beings but are applied to livestock and pets as well. When vaccines were first invented, their purpose was to stop the spread of infectious diseases. But today, the range of application of vaccines has grown beyond that. Ongoing research tackles prevention of non-infectious conditions such as cancer, Alzheimer’s disease or even cocaine addictions. The major future challenges to vaccine research are with relation to HIV/AIDS, tuberculosis and malaria.