UPSC Prelims 2021 Q65: Science & Technology – Biotechnology & Genetics
- (a) 1 only
- (b) 2 only
- (c) Both 1 and 2
- (d) Neither 1 nor 2
Answer: (c) Both 1 and 2
Explanation
Recombinant Vector Vaccines
| Statement | Claim | Verdict | Detail |
|---|---|---|---|
| 1 | Genetic engineering used in their development | TRUE | Recombinant vector vaccines are created by inserting a gene encoding the pathogen's antigen into a harmless viral or bacterial vector using recombinant DNA technology (genetic engineering). |
| 2 | Bacteria and viruses used as vectors | TRUE | Both viral vectors (adenovirus, vesicular stomatitis virus, lentivirus, poxvirus) and bacterial vectors (attenuated Salmonella, BCG, Listeria) are used as delivery vehicles. Examples: Covishield (AstraZeneca, chimpanzee adenovirus vector), Sputnik V (Ad5 + Ad26 vectors), Ebola vaccine (VSV vector). |
Both statements are correct. Answer: (c).
Vector vaccines are one of four major vaccine platforms: (i) inactivated/attenuated, (ii) subunit/protein, (iii) mRNA (Pfizer, Moderna), (iv) viral/bacterial vector.
Answer: (c) Both 1 and 2.
Why each option is right or wrong
- (a) Incorrect. Statement 2 (both viruses and bacteria used as vectors) is also correct.
- (b) Incorrect. Statement 1 (genetic engineering) is also correct - vector vaccines are quintessential rDNA products.
- (c) CORRECT. Both statements are true. Recombinant vector vaccines use genetic engineering to insert pathogen antigen genes into viral (adenovirus, VSV) or bacterial (BCG, Salmonella) vectors. Covishield and Sputnik V are Adenovirus-vectored COVID vaccines.
- (d) Incorrect. Both statements are factually correct.
Key point
Recombinant vector vaccines = rDNA-engineered viral/bacterial vector carrying pathogen antigen gene. Both statements TRUE. Examples: Covishield (chimp adenovirus), Sputnik V (Ad5+Ad26), Ebola VSV vaccine, Cervarix (papillomavirus).
Remember
Recombinant vector vaccines use (1) genetic engineering to insert antigen genes into (2) viral or bacterial vectors. Both statements are correct. Examples include Covishield (chimpanzee adenovirus vector) and Sputnik V (human Ad5/Ad26 vectors). Answer: (c) Both 1 and 2.
Common mistakes
- Confusing viral vector vaccines (Covishield) with mRNA vaccines (Pfizer, Moderna) or protein subunit vaccines (Corbevax).
- Not knowing bacterial vectors are also used - though less common than viral ones.
- Assuming genetic engineering is only for GMO crops. It underlies most modern vaccines, biologics and gene therapy.
Exam tip
Vaccine platforms: (i) Inactivated (Covaxin), (ii) Live attenuated (BCG, MMR), (iii) Subunit/Protein (Hep B, Corbevax), (iv) mRNA (Pfizer, Moderna), (v) Recombinant Vector (Covishield, Sputnik V), (vi) DNA (ZyCoV-D). All except (i) and (ii) involve genetic engineering.
Sources
- WHO - Vaccine Types and Development Pipeline
- ICMR - COVID-19 Vaccines: Platform Technologies