Vaccine and its role in immunity

In this era, pathogens are everywhere around us including our body, and several life-threatening diseases are seeking chances to attack us. Thanks to biological science and its discovery, we can fight them off with the help of several medications and vaccination doses. Among them, vaccines play a vital role in the prevention of several life-threatening diseases. Almost every one of us is aware of the word vaccine, but do you know what vaccine actually is? And, how do they protect us from disease-causing pathogens?

 

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What is a vaccine?

Biological agents that trigger our body's immune system to produce an immune response against a particular antigen are known as vaccines [Czochor J & Turchick A, 2014]. The vaccine is generated from a pathogen that causes an infectious disease. It helps in immunization, which means the vaccinated person is protected from that specific disease.

The process by which a vaccine is introduced into our body to protect us from a particular disease is called vaccination [Vaillant et al., 2022].

 

Origin of vaccine

‘Vaccine’ word was derived from the Latin word ‘Vacca’ which means cow [Saleh et al., 2021].

The story behind vaccine discovery [Saleh, 2021]

In May 1796, Edward Jenner met a girl named Sarah Nelms. Sarah had new cowpox wounds, Jenner collected matter from the fresh wounds, and he injected that matter to an 8-year-old boy whose name was James Phipps, later James suffered from mild fever and pain in the injected part, and after a few days felt cold and he lost his appetite, but next day he felt much better.

 

https://denstoredanske.lex.dk/Edward_Jenner

 

In July 1796 Jenner injected James again, but now the matter was collected from a smallpox wound. James was totally fine and didn't get any disease, so Jenner concluded that the protection was complete.

 

How do vaccines work in our bodies?

Vaccines are weak or inactivated parts of an antigen (particular organism), that produce an immune response in our body. This inactivated part of the antigen cannot cause the disease in our body, but it will trigger our immune system to respond the same as it will react with the first encounter with the actual pathogen.

https://commons.wikimedia.org/wiki/File:WHO_EN_Vaccines_Topic_Two_Antigens_static_8Dec2020.jpg

 

Some vaccination process comes with several doses of vaccine which are given weeks or months apart. It is needed for the development of long-lived antibodies and the production of memory cells. With the help of vaccination, we can train our body to fight a specific disease-causing pathogen, and in the future when our body comes in contact with the actual pathogen our body can easily fight the pathogen.

 

What are the ingredients in a vaccine?

A vaccine contains several ingredients, such as,

·      Antigen - all vaccines contain an active antigen. Antigen triggers the immune response. The antigen can actually be a protein or sugar of the pathogen or can be a whole organism in an inactivated form.

https://commons.wikimedia.org/wiki/File:WHO_EN_Vaccines_Topic_Two_Ingredients_static_8Dec2020.jpg

 

 

·      Preservatives- These prevent the vaccine from being contaminated after the vial has been opened. Stabilizer- They protect the vaccine from any kind of chemical reaction.

·      Surfactants - they help in the blending of the ingredients of the vaccine

·      Diluents - it is used to dilute the vaccine to the required concentration. Sterile water is the most common diluent.

·      Adjuvant- it improves the immune response ability of the vaccine. Generally aluminum salts like Aluminium phosphate, Aluminium hydroxides are used as an adjuvant.

 

How are vaccines developed?

Vaccines undergo several tests and evaluations before use. if the vaccine is capable of producing an immune response it is then tested in humans. This trial test is done in three phases

Phase 1

In this phase, a small amount of the vaccine is given to a small number of young healthy volunteers and tested if it is safe and can produce an immune response or not

Phase 2

In this phase, the vaccine is applied to several hundred volunteers to check its safety and ability to produce an immune response. Here the volunteers are divided into groups according to their age sex etc.

 Phase 3

The vaccine is now applied to thousands of volunteers of the same age or sex group as phase 2.

After the trials are over and the output is finalized, the reports are sent for approval by the public health officials. After the approval, the vaccine comes under use.

 

What are the side effects of vaccination?

It is not like everyone experiences the side effects after getting a vaccine dose, but some people do. 

The most common side effects are

At the place where the vaccine was injected –

1. Pain

2. Redness

3. Swelling

rest of our body –

1. Tiredness

2. Headache

3. Muscle pain

4. Fever

5. Chills

Allergic reaction – Though it's very rare but sometimes few people experience severe allergic reactions. If this happens to anyone, then that person should not take further doses of the vaccine.

Adverse effects - It's rare but can cause long-term health problems.

 

Tips to relieve side effects

To reduce pain in the injected part –

1. Clean, weight, and cool cloth can be applied in that area.

2. Move or exercise the injured part.

To reduce the discomfort of the body –

1. Drink lots of water and healthy liquid.

2. Dress lightly.

 Medications – After consulting a doctor, medicine such as Paracetamol, Ibuprofen, Aspirin (for adults only), etc. can be taken.

 

Why do some people get a fever after taking a vaccine?

When we take a vaccine shot the antigen present in the vaccine triggers an immune response in our body. This immune response helps in the production of immune cells to fight off the disease and the blood circulation of our body is increased to circulate the immune cells throughout our body. This increased circulation can increase body temperature which consequently shows up as fever.

 

List of a few important vaccines –

Name of vaccine	Disease	Year of discovery
BCG	Tuberculosis	1921
Hep B	Hepatitis B	1986
Polio	Poliovirus	1955
DTP	Diphtheria, Tetanus, Pertussis	1948
Hib	Haemophilus influenza type b	1892
Pneumococcal	Meningitis, Pneumonia	1977
Rotavirus	Rotavirus	1998
MMR	Measles, Mumps, Rubella	1963
HPV	Human papilomavirus	2006
COVAXIN , Covishield	Covid-19	2020

Can someone get infected by disease even after vaccination?

No vaccine gives a 100% guarantee that it will fully protect us from that disease, so there are chances that one can get a disease even if that person was fully vaccinated.

What will happen if someone skips a vaccine dose?

If a vaccination process consists of two or more doses of vaccine shots, skipping a vaccine dose may lead us to get the disease more quickly than someone who has received all the doses of the vaccine and is fully vaccinated.

so, getting all the doses of the vaccine is very important for everyone.

There are several misconceptions about vaccines that are totally wrong. such misconceptions are-

1. Vaccines can make you sick.

2. They contain toxic substances.

3. They overload your immune system.

4. Natural immunity is more effective than the immunity provided by vaccines.

5. If everyone around me is vaccinated that I don't need to be vaccinated.

Conclusion-  Thanks to vaccines we can protect ourselves from several diseases. They protect us as shields and make our immune system strong. so, vaccination is very important to fight off disease, and negligence in taking vaccines can lead us to very dangerous diseases, so it is very necessary to take all recommended vaccines.

Reference:-

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