What Happens in Your Immune System When You Are Vaccinated?

Vaccines help the body to recognise and fight incoming pathogens. They actually teach the immune system to identify and have a memory of the viruses should they reenter in the future. This is nothing but an acquired immune response.

What Are Vaccines, and How Do They Work?

Vaccines are small, weakened parts of an entity. Mostly, they comprise an inactivated or weakened form of a bacterium or virus which is incapable of causing any disease – that is, the antigen.

These vaccines work by triggering a response from the immune system to a bacterium or a virus. This action generates a memory in the immune system, which further allows the body to “remember” a particular bacterium or a virus to protect against it and prevent it from causing the disease.

Response of the immune system to vaccines 

When a person is vaccinated, the immune system of the person identifies the antigen to be a foreign particle. In response, it activates the immune cells for them to kill the bacteria or viruses that are causing the diseases and synthesises antibodies. When viruses or bacteria enter the body, they attack and multiply. This entry and invasion are what cause a disease. 

The immune system fights infections using the white blood cells of the body. These white blood cells mainly comprise lymphocytes and macrophages. These cells swallow up the pathogens and leave the antigens. The immune system of the body recognises the antigens to be foreign substances and triggers the antibodies to attack them. B and T lymphocytes are defensive white blood cells which fight off infections.

Vaccines protect against some diseases by imitating infections. It teaches the immune system to fight future infection. At times, even after vaccination, such an infection can lead to minor signs like fever which are normal and expected as the body is starting to build up immunity.

Usually, it takes some weeks for the body to synthesise lymphocytes after vaccination. Hence, it is not possible that a person that is infected with a disease before or after vaccination can develop signs and symptoms and get inflicted by that disease, as the vaccine did not have enough time to provide protection. No vaccine is perfect, even though they are deemed to be one of the safest ways to protect from diseases. 

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How to Get a Vaccine?

Vaccines can be administered as injected vaccines or in the form of nasal or oral vaccines.

Oral vaccines 

Liquid vaccines are administered from a dropper in the mouth and are to be swallowed. They are effective for diseases which affect the gut. However, these are difficult to synthesise, as they must get past the acids in the stomach to bring about a strong immune response.

Injected vaccines 

Most of the vaccines are intramuscular shots, as a few immune cells reside in the muscles. They are injected in the arm usually. Your skin is cleansed with an alcoholic swab, and you are given a shot – inoculation – in the muscle. 

Nasal vaccines 

A mist is sprayed up the nose to administer the nasal vaccine, which causes an immune response in the body. It can also provide surplus protection with an immune response that lines the airways and nose.

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