Question 92 from UPSC CSE 2021 - Current Affairs

Question

With reference to recent developments regarding 'Recombinant Vector Vaccine', 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?

IASCODEX · Accepted Answer

Correct Option: C. Both 1 and 2

Strategy: - Focus on the term 'recombinant vector vaccine'.
- Deconstruct 'recombinant' to mean genetic engineering.
- Deconstruct 'vector' to mean a carrier organism for genetic material.
- Validate statements by confirming that vectors can be both bacteria and viruses.

Key Info: Recombinant vector vaccines are a class of advanced, genetically engineered vaccines. They work by inserting genetic material encoding antigenic proteins of a pathogen (for example, a virus that causes disease) into a harmless carrier organism—known as the vector.

- **Genetic Engineering:** The process involves splicing genes that encode crucial antigens from the target pathogen into the genome of the vector. Modern recombinant DNA technology ensures precision and safety. This method allows the production of specific proteins that can induce an immune response without causing the disease. Thus, genetic engineering is fundamental to the development of such vaccines.

- **Vectors Used:** Bacteria and viruses are commonly used as vectors. Viral vectors include adenovirus (used in COVID-19 vaccines like Oxford-AstraZeneca's Covishield/ChAdOx1), measles virus, and modified vaccinia Ankara. Bacterial vectors, though less commonly used in licensed human vaccines, are also used in research and veterinary applications. The vector organism carries and expresses the inserted foreign gene when administered to the host, stimulating immune responses to the encoded protein.

- **Immunological Advantage:** Compared to subunit vaccines, recombinant vector vaccines can elicit both humoral and cellular immune responses. This enhances vaccine efficacy and memory. Importantly, because these vectors can be engineered to be non-replicating or attenuated, they generally pose reduced safety risks compared to live attenuated vaccines.

- **Examples:** The rVSV-ZEBOV Ebola vaccine employs vesicular stomatitis virus (VSV) as a vector. Several COVID-19 vaccines such as Sputnik V, Johnson & Johnson's Ad26.COV2.S, and CanSino use adenoviral vectors. Rabies and HIV vaccine research also utilizes this platform.

- **Regulatory and Scientific Context:** Recombinant vector vaccines are extensively evaluated for safety, immunogenicity, and ability to induce a robust response while minimizing adverse effects. Their development is strictly regulated by agencies like WHO, US FDA, and India's DCGI.

These features underscore the importance and relevance of recombinant vector vaccines in the current landscape of public health and emerging infectious disease control.

IASCODEX · Answer

Option A: 1 only

IASCODEX · Answer

Option B: 2 only

IASCODEX · Answer

Option D: Neither 1 nor 2

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

With reference to recent developments regarding 'Recombinant Vector Vaccine', consider the following statements:

Genetic engineering is applied in the development of these vaccines.

Bacteria and viruses are used as vectors.
Which of the statements given above is/are correct?