It all starts with taking a breathe
Starts lodging in mouth and throat
Began to move from cell to cell and replicate
After 12 days...
Will began to enter in the bloodstream
From there it will multiply in the bone marrow and spleen.
You will notice high fever, muscle pain, headache, and weakness.
Spots will start to appear in the mouth and throat.
Will rupture and release the virus into saliva.
Last it will attack in the skin.
Variolation technique
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How was the first vaccine discovered - It is smallpox a deadly virus with death rates ranges from 30% to 90%. The only Known solution to this virus was the Variolation technique. This procedure was brought to England by lady Mary Wortley Montagu.


Smallpox
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In this technique, a doctor would cut and open the pustule of an infected person and dry the extracted material (pus) and rub on the arm of a healthy person.

Then the healthy person will face mild symptoms of smallpox for a few days and he/she will become immune lifetime.

But the main problem was, that person would require a period of quarantine and some caretakers, thus making vulnerable to caretakers to get infected with that virus. Survivors from this virus suffer from loss of eyelashes, blindness, or even permanent scars.

To maintain all this, a person needs to be rich. The poor population couldn't afford this technique. This technique was not very effective, but something is better than nothing. Only around 2% of people died from this procedure than 14% from natural infection.

In the 18th century, it is estimated that around 400,000 death/ year was recorded in Europe due to smallpox.

Edward Jenner an English doctor observes something in milkmaid and shepherds, they were immune to this virus. He continued his observation and he again noticed something, a disease name cowpox was very common to have in cows and sheeps and thus was very common to see in milkmaids.

Edward Jenner
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After his observation, he concluded that those shepherds or milkmaid who was having cowpox or has gone through it was totally immune to smallpox. Therefore, his conclusion was smallpox and cowpox was a similar virus to the human immune system.

Later on, he did an experiment on 8yr old boy named James Phipps, he injected cowpox in the body of James and waited for a few months. After a few months, he injects the virus of smallpox in the body of James and waited for someday to get the symptoms of smallpox but the body of James was showing only mild symptoms but it was not smallpox.

Edward Jenner gave name to this process as Vaccination. The vaccine word comes from the Latin word vacca which means cow.

This was the first official vaccine invented by Jenner and soon after it began to use worldwide. Finally in 1980, WHO declared that there is no case of smallpox.

This was how our first vaccine was discovered.

If more curious about viruses then you must go to What are a virus to know every detail about viruses.