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?
Contents18
- A1 only
- B2 only
- CBoth 1 and 2
- DNeither 1 nor 2
Show answer
Answer: (C) Both 1 and 2
Statement 1 is correct:
Recombinant vector vaccines use genetic engineering.
Scientists insert the gene for a pathogen's antigen (like a spike protein) into a harmless virus (the vector).
When this engineered virus enters the body, it produces the pathogen's protein, triggering an immune response.
Statement 2 is correct:
The vectors used are typically weakened or modified viruses or bacteria.
For example, the Oxford-AstraZeneca COVID vaccine used a modified chimpanzee adenovirus as vector.
The body responds with both antibody and cellular immune responses.
Both statements are correct.
Answer: (c).
Recombinant vector vaccines like Oxford-AstraZeneca and Johnson & Johnson's COVID-19 vaccines use genetic engineering to insert pathogen genes into harmless viruses or bacteria that serve as delivery vehicles.
COVID-19 vaccines brought recombinant vector technology into global focus in 2020-21, making this a highly relevant current affairs topic for the 2021 UPSC exam.
The question tests understanding of the dual biotechnology concept: genetic modification of vectors and the biological carriers used in modern vaccine development.
Recombinant Vector Vaccines
Science And Technology Recombinant Vector Vaccine vectors
Recombinant Vector Vaccines: Mechanism & Examples
Recombinant vector vaccines use genetic engineering to insert pathogen genes into harmless viruses or bacteria
Vectors are weakened/modified viruses or bacteria that carry the antigen gene into human cells
Oxford-AstraZeneca and Johnson & Johnson COVID vaccines are vector vaccines
Triggers both antibody and cellular immune responses
Basic Mechanism
Recombinant vector vaccines combine genetic engineering with live vectors to deliver immunity. Scientists take a gene from a dangerous pathogen (like SARS-CoV-2 spike protein gene) and insert it into a harmless virus or bacterium called a vector. When injected, the vector enters human cells and uses the cell's machinery to produce the pathogen's protein, training the immune system to recognize and fight the real pathogen.
Vaccine Development Process
%%{init: {"flowchart": {"wrappingWidth": 460}}}%%
flowchart TD
s1["`**Gene Selection**
Identify and isolate the gene coding for pathogen's antigen (e.g., spike protein)`"]
s2["`**Vector Engineering**
Insert the antigen gene into a harmless virus/bacteria using genetic engineering`"]
s3["`**Vector Delivery**
Modified vector is injected and enters human cells`"]
s4["`**Protein Production**
Human cells produce the pathogen's protein using the inserted gene`"]
s5["`**Immune Response**
Body recognizes foreign protein and creates antibodies + T-cell immunity`"]
s1 --> s2
s2 --> s3
s3 --> s4
s4 --> s5Common Vector Types
Vector Type | Examples | Vaccine Example | Key Feature |
|---|---|---|---|
Adenovirus | Human adenovirus, Chimpanzee adenovirus | Oxford-AstraZeneca, Johnson & Johnson | Cannot replicate in human cells |
Modified Vaccinia Ankara (MVA) | Poxvirus vector | Some experimental vaccines | Highly attenuated, safe |
Bacterial vectors | Salmonella, E. coli | Oral vaccine research | Can be administered orally |
Key Advantages
Dual immunity: Produces both antibody and T-cell responses, unlike some other vaccine types
Single dose potential: Some vector vaccines provide long-lasting immunity with one shot
Stable storage: More stable than mRNA vaccines, easier cold chain management
Established safety: Vector technology has been used safely in other vaccines for years
Trap: Confusing vector vaccines with live attenuated vaccines - vector vaccines use engineered carriers, not weakened whole pathogens
Trap: Thinking only viruses can be vectors - bacteria like Salmonella are also used as vectors
Trap: Assuming the vector itself causes disease - vectors are harmless or severely weakened
Both statements in the question are correct because genetic engineering AND biological vectors are both essential
Genetic Engineering in Vaccine Development
Science And Technology Genetic engineering
Genetic Engineering Applications in Modern Vaccines
Genetic engineering enables precise insertion of pathogen genes into vaccine vectors
Recombinant DNA technology is the core technique used in vector vaccine development
Modern vaccines increasingly rely on genetic engineering for safety and precision
Role in Vector Vaccines
Genetic engineering is essential for creating recombinant vector vaccines. Scientists use recombinant DNA technology to cut and paste specific genes from dangerous pathogens into harmless vectors. This precise gene manipulation allows vaccines to produce only the necessary antigens without any risk of causing the actual disease.
Genetic Engineering Vaccine Types
Vaccine Type | Genetic Engineering Role | Example | Key Technique |
|---|---|---|---|
Vector vaccines | Insert antigen gene into viral/bacterial vector | AstraZeneca COVID vaccine | Gene insertion into adenovirus |
mRNA vaccines | Create synthetic mRNA coding for antigen | Pfizer, Moderna COVID vaccines | mRNA synthesis and delivery |
Recombinant protein vaccines | Produce antigen proteins in lab using engineered cells | Hepatitis B vaccine | Protein expression in yeast/bacteria |
DNA vaccines | Direct injection of engineered DNA | Some experimental vaccines | Plasmid DNA construction |
Technical Advantages
Precision: Only specific antigen genes are used, eliminating unnecessary pathogen components
Safety: No live dangerous pathogen is used in vaccine production
Speed: Once gene sequence is known, vaccine development can begin immediately
Scalability: Engineered vectors can be mass-produced in laboratory conditions
Trap: Thinking genetic engineering is only used in mRNA vaccines - it's used in vector, protein, and DNA vaccines too
Trap: Confusing genetic engineering with genetic modification of humans - vaccines don't alter human DNA permanently
Viral and Bacterial Vectors in Vaccines
Science And Technology Bacteria viruses vectors
Biological Vectors: Viruses & Bacteria as Vaccine Carriers
Adenoviruses are the most common viral vectors in approved vaccines
Bacterial vectors like Salmonella are used for oral vaccine research
Vectors must be weakened or modified to prevent disease while maintaining delivery function
Vector Requirements
Biological vectors must meet strict criteria: they should efficiently enter human cells to deliver the antigen gene, but be harmless to the recipient. Viruses are naturally good at entering cells, while bacteria can be engineered to target specific tissues or provide oral delivery routes.
Viral Vectors Comparison
Vector Type | Source | Advantages | Vaccine Examples |
|---|---|---|---|
Human Adenovirus | Common cold virus (weakened) | Well-studied, strong immune response | Johnson & Johnson COVID vaccine |
Chimpanzee Adenovirus | Modified chimp adenovirus | No pre-existing human immunity | Oxford-AstraZeneca COVID vaccine |
Modified Vaccinia Ankara | Poxvirus (highly attenuated) | Cannot replicate, very safe | Smallpox, some experimental vaccines |
Vesicular Stomatitis Virus | Animal virus (modified) | Strong single-dose response | Ebola vaccine (rVSV-ZEBOV) |
Bacterial Vectors
Bacterial Vector | Natural Properties | Vaccine Application | Delivery Route |
|---|---|---|---|
Salmonella (attenuated) | Invades intestinal cells | Oral vaccine research | Oral administration |
E. coli (modified) | Easy genetic manipulation | Laboratory antigen production | Produced proteins extracted |
Lactobacillus | Naturally safe gut bacteria | Mucosal immunity research | Oral/nasal delivery |
Bacillus (spores) | Heat-stable spore formation | Stable vaccine storage | Oral delivery |
Vector Advantages by Type
Viral vectors: Natural cell entry mechanisms, strong immune activation, established safety data
Bacterial vectors: Oral delivery possible, target specific tissues, cost-effective production
Replication-defective vectors: Cannot multiply in human body, safer for immunocompromised patients
Non-human vectors: Avoid pre-existing immunity that could reduce vaccine effectiveness
Both viruses AND bacteria can serve as vectors - don't limit thinking to just viruses
Trap: Assuming vectors cause the original disease - they are weakened/modified to be harmless
Trap: Confusing vector vaccines with live attenuated vaccines - vectors carry foreign genes, not their own disease-causing genes
COVID-19 Vaccine Technologies
Science And Technology
COVID-19 Vaccine Platforms: Vector, mRNA & Protein-Based
Four main COVID vaccine types: Vector, mRNA, protein subunit, and inactivated virus
Vector vaccines (AstraZeneca, J&J) use modified viruses to deliver spike protein gene
mRNA vaccines (Pfizer, Moderna) directly deliver genetic instructions to cells
Covishield (AstraZeneca) and Covaxin (inactivated) are India's main vaccines
Major COVID-19 Vaccine Comparison
Vaccine | Technology | Doses | Efficacy | Storage |
|---|---|---|---|---|
Pfizer-BioNTech | mRNA | 2 doses, 21 days apart | ~95% | -70°C (ultra-cold) |
Moderna | mRNA | 2 doses, 28 days apart | ~94% | -20°C (freezer) |
Oxford-AstraZeneca | Viral vector (chimp adenovirus) | 2 doses, 4-12 weeks apart | ~70% | 2-8°C (refrigerator) |
Johnson & Johnson | Viral vector (human adenovirus) | 1 dose | ~66% | 2-8°C (refrigerator) |
Covaxin | Inactivated virus | 2 doses, 28 days apart | ~78% | 2-8°C (refrigerator) |
COVID Vaccine Technologies
# COVID-19 Vaccines
## Vector Vaccines
- AstraZeneca (Covishield)
- Johnson & Johnson
- Sputnik V
- Uses modified virus
## mRNA Vaccines
- Pfizer-BioNTech
- Moderna
- Direct genetic instruction
- Ultra-cold storage
## Inactivated Vaccines
- Covaxin (Bharat Biotech)
- Sinovac
- Killed virus particles
- Traditional approach
## Protein Subunit
- Novavax
- Corbevax
- Purified spike protein
- With adjuvantsIndia's Vaccine Program
Covishield: AstraZeneca vaccine manufactured by Serum Institute of India, most widely used
Covaxin: Indigenously developed by Bharat Biotech using inactivated virus technology
Corbevax: Protein subunit vaccine, developed by Biological E with Baylor College
Sputnik V: Russian vector vaccine, limited use in India during shortage periods
Trap: All COVID vaccines use the same technology - actually four different platforms were successfully deployed
Trap: Thinking mRNA vaccines are vector vaccines - mRNA delivers genetic material directly, vectors use carrier viruses
Covishield is the AstraZeneca vector vaccine made in India, not a separate Indian technology