Before going to how do vaccines works, let's have a look at how our immune system works.

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How our immune system works

Our immune system only has three things to do.

  1. Identify pathogens or viruses
  2. kill them.
  3. Remember them.

Whenever any pathogen or virus enters our body, our body will start to fight it by activating the Innate response.

The innate response will come into play immediately once the virus or pathogen enters our body. Due to this, we can get fever, inflammation, cold, sneezes, or cough.

Once we get these symptoms, we should know that our body has activated Innate response from the immune system to fight with outside virus.

But the picture doesnt end here, sometimes our Innate system is not enough to fight with the virus and to cure us, then our Adaptive immune system will come into play.

Our Adaptive immune system has a very special cell which can kill bacteria or virus, the cells are Helper T cells, B cells, Killer T cells, Dendritic cells.

Immune cells
Image source - Google | Image by autoimmune-encephalitis

Dendritic cells will try to detect bacteria by looking at antigens of any virus or bacteria. An antigen is a small part of any pathogen.

After detecting the pathogen, our system will begin to respond using helper T cells and B cells. B cells will start to multiply to make plasma cells and it will create proteins called antibodies.

These antibodies will bind to the antigen of the pathogen and will starts destroying it. After all this work, our system will create Killer T cells that have the ability to detect and destroy cells infected with the pathogen.

Not only this, our adaptive system will create memory cells which have the ability to remember the pathogen, to protect us from a pathogen in the future.

Till now we don't have any problem with our immune system so why do we require vaccines, because our adaptive system can be too slow to detect and destroy the pathogens.

Other than this, if anyone has weak immunity their immune system might fail to detect pathogen or can be even slower to respond.

Why do we require vaccines and how do vaccines works.

So here is the reason, we require vaccines because,

  1. To increase the speed of the adaptive system.
  2. To make familiar with the pathogen, then it will be easier to fight with the pathogen for our immune system.

There are many types of vaccines but,

  • Live attenuated vaccines
  • Inactive vaccines
  • Subunit vaccines
  • Toxoid vaccines.

These are the common types. Let's have a look and how do vaccines works.

  1. Live attenuated vaccines:-This vaccine consists of a weaker version of the pathogens. So that without harming our body it can activate an adaptive immune system but again, this vaccine can't be used on a weaker body. As it contains the pathogen itself.
  2. Inactive vaccines:- This vaccine consists of dead pathogens. Due to dead pathogens, this vaccine can be given to the weaker immune system. The main drawback of this vaccine is, it cannot create long lasting immunity.
  3. Subunit vaccines:- This vaccine is made up of only a small part of a pathogen called as peptide. It can activate the adaptive immune system with long-lasting immunity and can be applied even to the weaker immune system.
  4. Toxoid vaccines:- Some bacteria releases toxins, these toxins can be used as a trigger to activate the immune system by inactivating the toxins and uses as a vaccine.