What is the basic principle behind vaccine development ? How do vaccines work ? What approaches were adopted by the Indian vaccine manufacturers to produce COVID-19 vaccines ?
Approach · directive: “what / how”
What it asks · State the immunological principle behind vaccines, explain how they trigger protection, and outline the platforms Indian manufacturers used for COVID-19 vaccines.
The question has 3 parts — answer each
- What is the basic principle behind vaccine development
- How do vaccines work
- What approaches Indian manufacturers adopted to produce COVID-19 vaccines
Open with · A vaccine trains the immune system to recognise a pathogen without causing the disease, so the body responds faster and harder on real exposure.
Cover
- Principle: exposure to a harmless form or part of a pathogen (the antigen) prompts adaptive immunity and leaves memory cells; widespread immunity also gives herd protection.
- How they work: antigen-presenting cells alert helper T cells; B cells make antibodies and killer T cells destroy infected cells; memory cells persist, and boosters and adjuvants strengthen the response.
- Platforms in general: live attenuated, inactivated, subunit or protein, toxoid, viral vector, and DNA and mRNA vaccines.
- Covaxin (Bharat Biotech with ICMR and NIV Pune) is an indigenous inactivated whole-virion vaccine.
- Covishield (Serum Institute of India) is the Oxford-AstraZeneca viral-vector vaccine, using a chimpanzee adenovirus, made under licence.
- Others: ZyCoV-D (Zydus) is a DNA plasmid vaccine, Corbevax (Biological E) a recombinant protein-subunit vaccine, Sputnik V an adenovirus-vector vaccine produced by Indian partners, followed by mRNA and nasal candidates.
Close with · A mix of indigenous and licensed platforms gave India scale and choice, and strengthened its vaccine-making capacity.
Question: UPSC's CS (Main) 2022, GS Paper III — paper ↗. Approach: Minimalist IAS, checked 30 Sept 2026 (how we verify) — UPSC publishes no model answers. ·
Model answer · 234 words (UPSC limit 250) · Minimalist IAS
A vaccine trains the immune system to recognise a pathogen without causing the disease, so that on real exposure the body responds faster and harder.
Basic principle
- Exposure to a harmless form or part of a pathogen (the antigen) prompts adaptive immunity and leaves behind memory cells, so the body mounts a rapid secondary response on infection.
- Population effect: when enough people are immune, transmission falls and even the unvaccinated gain herd protection.
How vaccines work
- Antigen-presenting cells process the antigen and alert helper T cells.
- B cells make antibodies that neutralise the pathogen, while killer T cells destroy infected cells.
- Memory B and T cells persist for years; adjuvants strengthen the response and boosters renew waning immunity.
- Platforms: live attenuated, inactivated, subunit or protein, toxoid, viral vector, DNA and mRNA vaccines differ in how they present the antigen.
Indian approaches to COVID-19 vaccines
- Inactivated whole virion: Covaxin, developed indigenously by Bharat Biotech with ICMR and NIV Pune.
- Viral vector: Covishield, the Oxford-AstraZeneca chimpanzee-adenovirus vaccine, made under licence by the Serum Institute of India; Sputnik V, an adenovirus-vector vaccine, produced by Indian partners.
- DNA plasmid: ZyCoV-D (Zydus), a plasmid DNA vaccine.
- Protein subunit: Corbevax (Biological E), a recombinant protein-subunit vaccine.
- Later: mRNA and intranasal candidates followed, widening the toolkit.
A mix of indigenous and licensed platforms gave India scale and choice during the pandemic and left it with stronger vaccine-making capacity for the future.
Written by Minimalist IAS from facts checked at source (how we verify). UPSC publishes no model answers: compare your structure and coverage with this, then write your own.