1. The Serum Institute of India produced COVID-19 vaccine named Covishield using mRNA platform.
2. Sputnik V vaccine is manufactured using vector based platform.
3. COVAXIN is an inactivated pathogen based vaccine.
Which of the statements given above are correct?
(a) 1 and 2 only
(b) 2 and 3 only
(c) 1 and 3 only
(d) 1, 2 and 3
Ans: b
Explanation:
About Vaccines
- A vaccine is a biological preparation that improves immunity to a specific disease. It typically contains an agent that resembles a disease-causing microorganism and is often made from weakened or killed forms of the microbe. The agent stimulates the body’s immune system to recognize the agent as foreign, destroy it, and “remember” it so that the immune system can more easily recognize and destroy any of these microorganisms that it later encounters.
- vaccines are administered prior to infection. Their role is to prime the immune system to fight any future infections, so that they can be brought under control before the disease-causing microorganism have had a chance to multiply.
- Vaccines are of different types – killed Vaccines , attenuated Vaccines , toxoid Vaccines, subunit Vaccines, Conjugate Vaccines, experimental Vaccines , Valence Vaccines.
The different types of vaccines
There are three main approaches to designing a vaccine. Their differences lie in whether they use a whole virus or bacterium; just the parts of the germ that triggers the immune system; or just the genetic material that provides the instructions for making specific proteins and not the whole virus.
1. The whole-microbe approach
- Inactivated vaccine
- Live-attenuated vaccine
- Viral vector vaccine
1. Live-attenuated vaccines:
- Live-attenuated vaccines contain live pathogens from either a bacteria or a virus that have been attenuated or weakened.
- They are produced by selecting strains of a bacteria or virus that still produce a robust enough immune response but that does not cause disease.
- Attenuated viruses were one of the earliest methods of eliciting protective immune responses.
- Examples: Measles, mumps, and rubella (MMR) vaccine, varicella (chickenpox) vaccine.
2. Inactivated vaccines
- Inactivated vaccines take a live pathogen and inactivate or kill it. Then the vaccine is introduced to a human through a shot, the inactivated pathogen is strong enough to create an immune response, however, is incapable of causing disease.
- Examples: Polio vaccine, influenza vaccine, Covaxin.
Hence Statement 3 is correct.
3. Viral vector vaccines:
- Viral vector vaccines use a harmless virus to deliver to the host cells the genetic code of the antigen that one wants the immune system to fight against. Viral vectors are a gene delivery system, where information about the antigen is delivered, which triggers the body’s immune response.
- Examples: Ebola vaccine, COVID-19 vaccine (AstraZeneca and Johnson & Johnson), Covishield, Sputnik-V.
2. The subunit approach
A subunit vaccine is one that only uses the very specific parts (the subunits) of a virus or bacterium that the immune system needs to recognize. It doesn’t contain the whole microbe or use a safe virus as a vector. The subunits may be proteins or sugars ( polysaccharides), conjugate. Most of the vaccines on the childhood schedule are subunit vaccines, protecting people from diseases such as whooping cough, tetanus, diphtheria and meningococcal meningitis.
3. The genetic approach (nucleic acid vaccine)
Unlike vaccine approaches that use either a weakened or dead whole microbe or parts of one, a nucleic acid vaccine just uses a section of genetic material that provides the instructions for specific proteins, not the whole microbe. DNA and RNA are the instructions our cells use to make proteins. In our cells, DNA is first turned into messenger RNA, which is then used as the blueprint to make specific proteins example of mRNA vaccines are Comirnaty (Pfizer-BioNTech) and Spikevax (Moderna).
Hence statement 1 is incorrect & statement 2 is correct.
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