Eelaththu Nilavan | Britain.
□. Introduction: What is a Vaccine?
A vaccine is a biological preparation that protects against a specific disease. It typically contains weakened or modified components of a pathogen (such as viruses or bacteria), or parts of it (such as proteins or genetic material), that stimulate the body’s immune system to recognize and combat the actual pathogen if encountered in the future.
Vaccines help the body develop immunity without causing the disease itself.
■. How Vaccines Are Made – Stages and Technology
The production of a vaccine is a long, complex, and highly regulated scientific process involving multiple critical stages:
◇. Exploratory Stage:
Scientists study the disease-causing agent (pathogen), identifying its genes, proteins, and structure to target for immunization.
◇. Preclinical Testing:
Conducted on cell cultures and animal models to assess the safety and immune response of the candidate vaccine.
◇. Clinical Trials in Humans:
Phase I: A Small group of healthy individuals to assess safety and dosage.
Phase II: Larger group to evaluate immunogenicity and side effects.
Phase III: Thousands of participants were tested for efficacy, safety, and protection rates.
◇. Regulatory Approval and Manufacturing:
Regulatory authorities like the FDA, EMA, or WHO review the clinical data and approve the vaccine if it meets all standards.
◇. Post-Marketing Surveillance:
Even after approval, vaccines are continuously monitored for adverse effects and long-term protection.
■. Types of Vaccines – What Are They?
Vaccines are classified based on how they are made and what they contain:
◆.Type Description
Live Attenuated Vaccines Contain a weakened form of the live pathogen. Example: MMR, BCG.
Inactivated Vaccines Contain killed versions of the pathogen. Example: Polio (IPV), Hepatitis A.
Subunit, Recombinant Vaccines Contain only parts (proteins) of the pathogen. Example: Hepatitis B.
mRNA Vaccines Contain messenger RNA that instructs cells to produce a viral protein. Example: Pfizer-BioNTech, Moderna.
Viral Vector Vaccines use a different virus to deliver genetic material. Example: AstraZeneca, Sputnik V.
DNA Vaccines Use engineered DNA to trigger an immune response (still under research).
Intranasal Vaccines Administered through the nose stimulate mucosal immunity.
■. How Do Vaccines Work in the Human Body?
◆. When a vaccine is administered, it introduces a harmless version or part of a pathogen into the body.
◆. The immune system detects this and mounts a defense, producing T-cells, B-cells, and antibodies.
◆. It also creates memory cells that “remember” the pathogen.
◆. If the real pathogen enters later, the immune system responds rapidly and efficiently, preventing illness.
◆. This creates immunity without the person having to suffer the disease itself.
■. Importance of Vaccines – Medical and Social Significance
Prevent Death and Disability: Vaccines prevent diseases that can be deadly or disabling (e.g., measles, diphtheria).
Control Epidemics: Widespread vaccination builds herd immunity, protecting those who cannot be vaccinated.
Eradicate Diseases: Smallpox was eradicated globally due to effective vaccination.
Reduce Healthcare Costs: Preventing diseases lowers treatment costs and economic burdens.
Adapt to New Threats: Vaccines can be developed or updated to address emerging infectious diseases.
■.Current Vaccine Research and Innovations
◆ mRNA and DNA-Based Vaccines – The Future of Immunization:
Since the success of COVID-19 vaccines like Pfizer and Moderna, mRNA and DNA technologies are at the forefront.
These allow rapid development, are easier to manufacture, and are highly adaptable.
◆. Vaccines for Non-Infectious Diseases:
Research is ongoing to develop vaccines for genetic disorders, autoimmune diseases, and chronic illnesses like:
Alzheimer’s disease
Rheumatoid arthritis
Cancer (therapeutic cancer vaccines)
◆. Multivalent Vaccines:
These vaccines target multiple pathogens in a single shot, reducing the number of injections needed.
◆. Plant-Based and Herbal-Adjuvant Vaccines:
Universities like the University of Sydney are exploring the use of plant compounds and traditional herbs as vaccine boosters (adjuvants).
◆. Therapeutic Vaccines:
Unlike preventive vaccines, therapeutic vaccines aim to treat existing diseases, especially in fields like oncology and HIV.
■. Conclusion: A Global Wall of Protection
Vaccines represent one of humanity’s greatest achievements in public health. As the world faces new pathogens, genetic disorders, and environmental shifts, vaccines remain a powerful tool for protection. Backed by precise science, cutting-edge technology, and global collaboration, vaccines continue to protect billions of lives and promise hope for a disease-free future.
□ Eelaththu Nilavan □
09/06/2025
