UPSC Prelims 2021 GS Paper I · Q65 of 98 General Science medium

With reference to recent developments regarding 'Recombinant Vector Vaccines', consider the following statements : 1. Genetic engineering is applied in the development of these vaccines. 2. Bacteria and viruses are used as vectors. Which of the statements given above is/are correct?

  1. (a) 1 only
  2. (b) 2 only
  3. (c) Both 1 and 2 ✓ UPSC's answer
  4. (d) Neither 1 nor 2

Why the answer is (c)

• Recombinant vector vaccines insert a gene for a pathogen's antigen into a harmless carrier (vector) microbe, which then expresses the antigen inside the body to provoke immunity.

• Statement 1 is correct: creating such a vector requires genetic engineering (recombinant DNA technology).

• Statement 2 is correct: both viruses (adenovirus in Covishield/ChAdOx1, Sputnik V, J&J) and bacteria (attenuated Salmonella, BCG) serve as vectors.

• These vaccines mimic natural infection and produce strong cellular immunity without using the live pathogen.

• Hence both 1 and 2, option (c).

Why the other options are wrong

(a) 1 only
Statement 2 is also correct: bacteria and viruses are used as vectors.
(b) 2 only
Statement 1 is also correct: genetic engineering is essential.
(d) Neither 1 nor 2
Both statements are correct.

Asked in the GS Paper I of the UPSC Civil Services Preliminary Examination 2021, held on 10 October 2021. Question and answer key: Union Public Service Commission. Explanation: UPSC Answer Check.

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