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.
It asks 3 things — 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 adaptive immune system to recognise a pathogen without causing the disease; under Mission COVID Suraksha (Rs 900 crore) India turned this principle into four indigenous vaccines in two years.
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 platform-agnostic portfolio, public funding through DBT and BIRAC, and regulatory speed gave India scale and choice; making this a standing mission for future pandemics is Atmanirbhar Bharat in health.
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- PIB (January 2023): Mission COVID Suraksha delivered four indigenous vaccines: ZyCoV-D (the world's first DNA vaccine), Corbevax (India's first protein subunit vaccine), GEMCOVAC-19 (India's first mRNA vaccine) and iNCOVACC (the world's first intranasal COVID-19 vaccine).PIB, Ministry of Science and Technology (27 January 2023): India has developed four indigenous vaccines in just two years, Dr Jitendra Singh ↗“The four vaccines are- ZyCoV-D- World’s 1st and India’s indigenously developed DNA Vaccine, CORBEVAXTM-India’s first protein subunit vaccine, GEMCOVAC™-19 - World’s 1st and India’s indigenously developed mRNA vaccine and iNCOVACC-World’s 1st and India’s indigenously developed intranasal COVID-19 Vaccine”
- PIB (January 2023): Mission COVID Suraksha was announced at a total cost of Rs 900 crore under the Atmanirbhar Bharat 3.0 package.PIB, Ministry of Science and Technology (27 January 2023): India has developed four indigenous vaccines in just two years, Dr Jitendra Singh ↗““Mission COVID Suraksha” was announced by Government of India, at a total cost of Rs. 900 Crore, under Atmanirbhar Bharat 3.0 package.”
- PIB (January 2023): the mission also supported expansion of Covaxin manufacturing at Bharat Biotech's Malur facility and at Indian Immunologicals Limited, Hyderabad.PIB, Ministry of Science and Technology (27 January 2023): India has developed four indigenous vaccines in just two years, Dr Jitendra Singh ↗““Mission COVID Suraksha” also supported augmentation of manufacturing facilities for enhancement of COVAXIN® production at Bharat Biotech’s Malur facility and Indian Immunologicals Limited, Hyderabad”
- PIB (20 August 2021): ZyCoV-D's plasmid DNA platform can be adapted to mutations; interim Phase III results in over 28,000 volunteers showed 66.6% primary efficacy.PIB, Ministry of Science and Technology (20 August 2021): DBT-BIRAC supported ZyCoV-D developed by Zydus Cadila receives Emergency Use Authorization ↗“The plug-and-play technology on which the plasmid DNA platform is based can be easily adapted to deal with mutations in the virus, such as those already occurring. Interim results from Phase-III Clinical Trials, in over 28,000 volunteers, showed primary efficacy of 66.6 per cent”
- PIB (28 December 2021): Corbevax, India's first indigenously developed RBD protein sub-unit COVID-19 vaccine by Biological E, received DCGI approval for emergency use.PIB, Ministry of Science and Technology (28 December 2021): Mission COVID Suraksha supported Biological E's CORBEVAX receives DCGI approval for Emergency Use Authorization ↗“India’s first indigenously developed Receptor Binding Domain (RBD) protein sub-unit vaccine for COVID-19, CORBEVAX TM , developed by Biological E Limited, has received the Drug Controller General of India (DCGI) approval for Emergency Use Authorization (EUA).”
Question: UPSC's CS (Main) 2022, GS Paper III — paper ↗. Approach: Minimalist IAS, checked 3 Oct 2026 (how we verify) — UPSC publishes no model answers. ·
Model answer· 332words · Minimalist IAS
A vaccine trains the adaptive immune system to recognise a pathogen without causing the disease, so that real exposure meets a faster and stronger response. Under Mission COVID Suraksha (Rs 900 crore, Atmanirbhar Bharat 3.0), India turned this principle into four indigenous vaccines in two years (PIB, 2023).
Basic principle behind vaccine development
- Antigen without disease: a harmless form or part of the pathogen (the antigen) prompts adaptive immunity and leaves memory cells, so infection later meets a rapid secondary response.
- Platform choice: live attenuated, inactivated, subunit, toxoid, viral-vector, DNA and mRNA vaccines differ only in how they present the antigen.
- Population effect: when enough people are immune, transmission falls and even the unvaccinated gain herd protection.
How vaccines work
- Antigen enters
- antigen-presenting cells alert helper T cells
- B cells make antibodies, killer T cells clear infected cells
- memory B and T cells persist
- faster response on real infection
- Antibodies and T cells: antibodies neutralise the pathogen while killer T cells destroy infected cells.
- Adjuvants and boosters: adjuvants strengthen the first response and boosters renew waning immunity.
Approaches adopted by Indian manufacturers for COVID-19 vaccines
- Inactivated whole virion: Covaxin, developed indigenously by Bharat Biotech with ICMR and NIV Pune; the mission also expanded its production at Bharat Biotech's Malur plant and Indian Immunologicals, Hyderabad.
- 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), the world's first DNA vaccine, whose plasmid makes the spike protein; interim Phase III efficacy was 66.6% in over 28,000 volunteers (PIB, 2021).
- Protein subunit: Corbevax (Biological E), India's first receptor-binding-domain protein sub-unit vaccine, approved for emergency use in December 2021.
- mRNA and intranasal: GEMCOVAC-19, India's first mRNA vaccine, and iNCOVACC, the world's first intranasal COVID-19 vaccine (PIB, 2023).
A platform-agnostic portfolio, public funding through DBT and BIRAC, and regulatory speed gave India scale and choice; making this a standing mission for future pandemics is Atmanirbhar Bharat in health.
Prepared by Minimalist IAS to the answer standard of Shivam Singh (mentor, 7 years) · facts checked against official sources (how we verify) · updated 3 Oct 2026. UPSC publishes no model answers: compare your structure and coverage with this, then write your own.
