Immunity is the main mechanism of host defense against infectious agents.
The body defends itself from infectious agents by battling against it with one’s own immune system. The immune system protects the body from infectious agents that exist in the environment (bacteria, viruses, fungi, parasites) and from other noxious insults.
The immune system has two functional divisions: Passive and Acquired. Both components involve various blood-borne factors (complement, antibodies, cytokines) and cells.
The acquired immune response has the ability to specifically recognise a pathogen (bacteria or virus) and ‘remember’ it if exposed to it again. T-cells (immunity cells) are critical in the recognition of the enemy and the co-ordination of this immune response. In this type, live vaccines are used i.e., the microorganisms are introduced into one’s system. The immune response produces resistance to make sure that in the future we don’t get affected by that particular bacteria or virus.
Active immunity plays an important role in immune responses in the event of re-exposure and our utilization of vaccines.
Passive immunization prevents disease via interaction between the administered antibodies (Vaccines) and invading microorganisms (viruses and bacteria). Passive immunization is able to provide immediate and effective protection.
Depending on the virulence of the pathogen and multiple other factors vaccines are made to be effective with lesser side effects. Immunity acquired or passive works towards resistance to the infection and reduce the consequences of infection.