Immunity is the capability of multicellular organisms to resist harmful microorganisms. These microorganisms can be bacteria and viruses which can harm the human body and Immunity in the body of a human being saves him/her from these bacteria and viruses. In simple words, we can say that immunity is the ability of the host to fight harmful viruses and bacteria or pathogens conferred by the immune system of the host. 

Immunity-Types of Immunity 

 Immunity is the ability of the host to fight harmful viruses and bacteria or pathogens conferred by the immune system of the host. There are two types of immunity in our immune system. They have innate immunity and acquired immunity. Innate immunity is the Immunity with which a person is born. Acquired immunity is the Immunity that we acquire or learn from our daily life or throughout the life journey. Acquired immunity is memory-based for example if someone is affected by Chicken Pox for once then that person will not be affected by that disease again in his/her life. There are two more types of immunities that come under the domain of acquired immunity. Total there are four types of Immunity. They are active immunity and passive immunity. 

The Four Types of Immunity are as follows: – 

  • In active immunity, Immunity is created by a person’s immune system when they come in contact with harmful pathogens. Humans are exposed to these throughout the day, it can be caused by eating, breathing, or touching. But luckily most of these organisms cannot harm the human body and they won’t have any harmful diseases because the human immune system works to throw them out of the body. Another important feature of active immunity is that it remembers a disease for a lifetime as a result if a person is affected by a disease once then he won’t be affected again by the same disease because of its strong memory. These memories contain B and T cells which help in recognizing the disease. 

The importance of Active Immunity are as follows: – 

  • It gives a quick response to an outside invader
  • It is highly specific, so the immune system is ready when the pathogen is encountered 

The thing which drives active immunity is vaccines. When a vaccine is injected into someone’s body their immune system treats it as exposure at the same time it generates an immunological memory. 

  • Passive Immunity is immunity that is earned by something other than one’s immune system. Unlike Active Immunity, passive immunity is short-lived immunity because the antibodies in this type of immunity are not continuously updated, as would occur in an individual whose immune system is responding directly. Passive Immunity can come from maternal antibodies which means antibodies which are transferred to a child’s body when he is inside his mother’s womb two types of antibodies are transported they are the placenta and breast milk. 
  • Innate Immunity is the Immunity with which a person is born. Innate immunity is made up of various restrictions that defend the body against viruses, bacteria, fungi, parasites, etc, and block their paths so that they cannot move and spread throughout the body. 
  • Acquired Immunity is the Immunity that we acquire or learn from our daily life or throughout the life journey. Acquired immunity is memory-based for example if someone is affected by Chicken Pox for once then that person will not be affected by that disease again in his/her life. 

Types of Immunisation 

Immunisation is the process by which a person’s immune system gets aware of the infectious agents so that if the infection tries to enter a person’s body again then these vaccines will not allow them to do that and as result, the person will not get affected by the same disease again or that infection never enters the person’s body again. Vaccination is active type immunity.

  • Inactivated Vaccines
  • Live-attenuated vaccines
  • Messenger RNA vaccines—also called mRNA vaccines 
  • Subunit, recombinant, polysaccharide, and conjugate vaccines 
  • Toxoid vaccines
  • Viral vector vaccines

Conclusion 

In simple words, we can say that immunity is the ability of the host to fight harmful viruses and bacteria or pathogens conferred by the immune system of the host.  Immunity is a complex biological system that can be recognized and tolerated once that belongs to the self, and to recognize and reject what is from foreign.