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How Covid-19 Vaccines Work?

How Covid-19 Vaccines Work? - IDEA clinics

Immune System

Blood contains red cells, which carry oxygen to organs, and white cells, which fight infection. Once vaccinated, body develops both T and B lymphocytes, the T-lymphocytes behave like memory cells and B-lymphocytes produce antibodies to attack the COVID-19 virus. White blood cells fight infection in different ways:

  • Macrophages are white blood cells that swallow up viruses inflicted cells and form antigens. The body identifies antigens as dangerous and stimulates antibodies to destroy them.
  • B-lymphocytes are different type of white blood cells which produce antibodies to attack the virus left behind by the macrophages.
  • T-lymphocytes are another type of white blood cells that attack cells in the body that have already been infected. 

Three main types of Vaccines

  • mRNA vaccines: 

These vaccines contain material from the virus that causes COVID-19, once injected the human body makes harmless proteins. Human bodies recognize that the protein should not be there, build T-lymphocytes and B-lymphocytes to fight the virus that causes COVID-19 if we are infected in the future.

  • Protein subunit vaccines 

These vaccines contain harmless portions of the virus that cause COVID-19 instead of the entire germ. Once vaccinated, the immune system recognizes that the proteins don’t belong in the body and begins making T-lymphocytes and antibodies, and provide with memory to fight the virus.

  • Vector vaccines 

These contain a dead version of live virus that has genetic material from the COVID-19 virus (Human Adeno viral vector). Once the viral vector is inside our cells, they prompt human bodies to build T-lymphocytes and B-lymphocytes that will remember how to fight the COVID-19 virus. 

Which Vaccine is The Best for India?

  • Moderna: (most expensive and most efficient) 95% efficacy but stored at -20 degrees and 2-8 degrees for a month, genetic code technology is unique.
  • Pfizer: (expensive) 94% efficacy but stored at -70 degrees, RNA based.
  • Sputnik V: (Cheap) 95% efficacy but stored at 2-8 degrees This Russian vaccine is produced by Dr. Reddy’s labs using viral vector technology.
  • Oxford/AstraZeneca: (Cheapest) 90% efficacy but stored at 2-8 degrees This Serum Institute of India, Pune is producing this vaccine using viral vector technology.

Russian Sputnik V and Oxford/AstraZeneca are the two vaccines that may be used by India and the third world.


(Condition specific – Doctor Led – AI Driven Health Care) Value-based healthcare is an approach to healthcare that focuses on delivering the best possible outcomes

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