Why do we no longer suffer from infectious diseases that were the obsession of the world in the last century such as smallpox and plague? That’s thanks to Vaccination.


In 1796, scientist Edward Jenner injected a substance taken from the smallpox virus into the body of an eight-year-old boy. This trial hopes to create a protective immune system and possibly save people from a dangerous outbreak of the smallpox virus. It was successful and became the first human vaccine.

Edward Jenner – the creator of the first vaccine.

How vaccines work

To understand how vaccines work, we must first understand how the immune system protects the body from infectious diseases.

When a virus or bacteria enters the body, the immune system activates a series of defense responses to recognize, destroy and eliminate them from the body. The signs for us to know that the immune system is working are manifestations: cough, sneeze, fever, …. This natural immune response also activates the adaptive immune system – our body’s second defense system.

T cells.

Then special types of cells called B cells and T cells are dispatched to fight the disease-causing microorganisms. Thereby they memorize information about their characteristics, structure and best way to destroy them. This information will be used the next time the same microorganisms enter the body.

That’s how vaccines work. Scientists use vaccines to activate the adaptive immune system without the body going through the entire infection process.

B cells.


There are many vaccines created based on the above mechanism, such as:

  • Live attenuated vaccine: Made from the same virus or bacteria that causes the disease but has been weakened.
  • Inactivated Vaccine: A vaccine in which bacteria or viruses have been killed.

These two vaccines were created to ensure that the pathogen would no longer be able to develop into a disease. However, it will trigger the immune system’s response like a real disease, teaching the body how to recognize attackers, destroy them and save the information as a preparation.

However, the live vaccine reduces the motivation, the pathogen is still alive, so the toxicity is very strong, not suitable for people with a weak immune system. Inactivated vaccines cannot provide lasting immunity. That’s why recombinant vaccines were born. This vaccine is made from a part of the pathogen called an antigen. This ingredient actually causes an immune response but has been modified to not be able to clone and cause disease anymore, but only carries certain genetic codes from which to activate the body’s immune system like two types. vaccines above.

Throughout history, humans have successfully developed vaccines for life-threatening diseases such as meningitis, tetanus, measles, etc. Therefore, each individual should be fully vaccinated, not only for protection. but also to protect the people around.

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