COVID-19 vaccines
The outbreak of the SARS-CoV-2 virus necessitated the fastest vaccine development and distribution program in global history. India conducted one of the world’s largest and most successful adult vaccination drives.
Understanding the underlying technology of the primary vaccines used in India is crucial, as they utilize different biological mechanisms to trigger the immune system.
Covishield:
Developed by Oxford University and AstraZeneca, and manufactured in India by the Serum Institute of India (SII).
1.Mechanism:
- It is a Viral Vector Vaccine.
- Scientists took a harmless adenovirus (which causes common colds in chimpanzees) and genetically modified it to carry the genetic code of the COVID-19 “spike protein.”
- When injected, the harmless virus delivers this code to human cells, tricking the body into producing the spike protein.
- The immune system then recognizes this protein as foreign, launching a primary immune response and creating memory B-cells.
Covaxin:
Developed entirely indigenously by Bharat Biotech in collaboration with the Indian Council of Medical Research (ICMR) and the National Institute of Virology (NIV).
1) Mechanism:
- It is an Inactivated Virus Vaccine.
- This represents a more traditional approach to vaccine manufacturing.
- The actual live SARS-CoV-2 virus was cultivated in a laboratory and then chemically killed (inactivated) so it could no longer replicate or cause disease.
- When injected, the dead virus particles are recognized by the immune system, triggering the production of antibodies.
ZyCoV-D:
Developed by Zydus Cadila, this marked a significant scientific milestone.
1)Mechanism:
- It is the world’s first plasmid DNA vaccine approved for human use.
- It uses a genetically engineered, non-replicating piece of DNA (plasmid) that carries the gene responsible for the spike protein.
Public Health Management (CoWIN)
A critical component of India’s COVID-19 immunization success was the CoWIN (Covid Vaccine Intelligence Network) digital platform. Moving away from traditional manual record-keeping, this cloud-based system facilitated real-time planning, implementation, scheduling, and monitoring of vaccine administration. It also generated universally verifiable digital vaccination certificates, setting a new global standard for digital public health infrastructure.
iNCOVACC
- It is an intranasal COVID-19 vaccine candidate developed by Bharat Biotech, American company Precision Virologics and the Washington University School of Medicine in St Louis, Missouri, United States.
- An intranasal vaccine stimulates a broad immune response – neutralizing IgG, mucosal IgA, and T cell responses.
- Immune responses at the site of infection (in the nasal mucosa) – essential for blocking both infection and transmission of COVID-19.
- The nasal route has excellent potential for vaccination due to the organized immune systems of the nasal mucosa.
- Non-invasive, Needle-free.
- Ease of administration – does not require trained health care workers.
- Elimination of needle-associated risks (injuries and infections).
