• Sairam Paluri

Why mankind is forever indebted to Vaccine?

In the article on Hand Hygiene, there is a mention of two basic weapons to fight against diseases - Hand Hygiene and Vaccines.

So what is a Vaccine? A vaccine is a preparation, that helps the immune system of our body to recognize and fight against pathogens(bacteria, virus).

How does the immune system recognize a pathogen?

Like a person having his/her own identity, a pathogen has its own identity like proteins on its surface.

What happens during a natural infection?

If a person encounters for the first time, the immune system of the person identifies the pathogen as foreign material and try to attack it. The body's defence mechanism(immune system) forms certain protein structures - Antibodies. These antibodies bind to antigen thus arrests the pathogen red-handed using its identification marks several processes occur and the body removes the pathogen from the body. This identification, production of antibodies, and the other processes take some time, even days.


The important feature that lies with the immune system is its 'Memory'.

Our immune system remembers the identification marks(antigens) of the pathogen and thus during the future encounters with the pathogen, the action is prompt without delay.


  • A vaccine contains either dead pathogens(inactivated type) or live weakened pathogen(attenuated), inactivated toxic compound(toxoids) etc...

  • These preparations when injected into the body don't cause any serious illness, they cause very mild infection when injected.

  • When a vaccine is injected, it mimics the natural infection(first encounter) but here it doesn't cause any illness to us. But our body thinks that a foreign body has entered our body and starts preparing antibodies.

  • Thus when this vaccinated person naturally encounters the pathogen there will be no delay in the response and the immunity takes over the pathogen preventing the disease.


Let's look into the history of the Vaccine...


Discovery of Vaccine-


Discovery of vaccine is one of the breakthroughs in the field of medicine. Without them, mankind is no more. In 1796, Edward Jenner - father of vaccinology observed that during the high prevalence of smallpox in the community, the milkmaids were found to show some resistance to the disease. Those milkmaids were found to have some mild infections with some blisters on their hands while milking the cows.


On investigating, Edward came to know that those cows were infected with cowpox virus. He got an idea and experimented by injecting this cowpox virus into a 13-year-old boy and the boy developed a mild infection. After a few days, he injected the deadly smallpox virus. He was shocked to observe that the boy didn't develop any illness.


Here cowpox virus and smallpox virus are closely related that the antibodies developed against cowpox virus, attacked the smallpox virus when injected, thus preventing the disease. Are you wondered? Yes, you may.


Similarly, does the vaccine(if developed) for SARS COV can work on SARS COV2?


Importance of Vaccine-

The discovery of vaccine occurred as a timely event, without its discovery by Edward Jenner, there may not be healthy mankind, I may not be writing this article or you may not be reading this article.

  • WHO estimates that vaccination prevents 2-3 million deaths every year.

  • Thanks to widespread vaccination around the world against smallpox(common and deadly infectious disease). This gives rise to the concept known as Herd Immunity, leading the eradication of smallpox.

  • It is estimated that from 1980 to now, this vaccination saved around 5 million lives per year. Therefore till now 240 -270 million lives have been saved.

  • Vaccination prevents many maternal and infant mortalities.

  • Eradication of Polio - Polio is one of the diseases targeted for the eradication.


Measles - Statistics:

Nearly everyone in the U.S got measles before there was a vaccine. In 1958, there were 7,63,094 cases of measles in the U.S. But after the introduction of the vaccine, the cases fell to less than 150 per year.



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