Vaccines and how they work

As you guys might be reading about vaccination drive for COVID-19, so what are vaccines?

Vaccine is a product that builds person’s immune system to fight back a particular disease. Vaccines are usually administered through needle injections, or through drops or nose sprays.

How are vaccines manufactured?

The whole idea of vaccine is to create antibody against particular disease without any illness. That is making person’s immune system well aware of antigen before-in-hand. So, following are the ways in which antigens can be used as vaccines:

a) Attenuated live virus: In this, virus is weakened and injected into the body. These do not cause disease but build immunity in person’s body.

b) Inactivated virus: A form of vaccine in which it is killed. It raises the antibody.

c)Recombinant: Recombinant vaccines are made using bacterial or yeast cells to manufacture the vaccine. A small piece of DNA is taken from the virus or bacterium against which we want to protect and inserted into the manufacturing cells. 

d)Conjugate: A conjugate vaccine is a type of vaccine which combines a weak antigen with a strong antigen as a carrier so that the immune system has a stronger response to the weak antigen.

e)Subunit: These contain only the antigenic parts of the pathogen. These parts are necessary to elicit a protective immune response.

f)Toxoid: Long-lasting immunity against bacterial diseases such as tetanus and diphtheria is induced by a course of toxoid vaccines which cause an immune response against weakened versions of specific bacterial toxins called toxoids.

Why there are multiple doses of vaccines?

There are multiple reasons for it:

1) It is studied that more than one doses build immunity very well.

2) For some vaccines, the immunity built is for shorter time. In that case booster immunity is must.

Infectious disease physician Carlos Malvestutto says, “The first dose primes the immune system while the second dose induces a vigorous immune response…” Essentially, a second dose provides more antibodies (also called immunoglobulins), which are “proteins produced by the immune system” in order to fight against foreign substances (antigens). Traditional vaccines contain either weak or inactivated versions of the pathogen (which can be a virus or bacteria), provoking an immune response, allowing the immune system to effectively deal with the pathogen if it enters the body again. It is often the inactivated vaccines that need multiple doses because they are not as close to the actual pathogen in comparison to vaccines that use weak, live versions of the pathogen.

How Vaccines work

Vaccines work by mimicking the infectious bacteria or viruses that cause disease. Vaccination stimulates the body’s immune system to build up defence against the infectious bacteria or virus without causing the disease. The parts of the infectious organism that the immune system recognizes are foreign to the body and are called antigens. Vaccination exposes the body to these antigens. After vaccination, the immune system is prepared to respond quickly and forcefully when the body encounters the real disease-causing organism.

This is brief introduction to vaccines.

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