Immunity is the body's ability to resist disease-causing organisms; a vaccine is a preparation that trains the immune system to recognise and fight a specific pathogen.
- A vaccine introduces a weakened, killed, or part of a pathogen (or its genetic instructions), prompting the body to make antibodies and memory cells without causing the disease.
- Active immunity is produced by the body itself (after infection or vaccination) and is long-lasting; passive immunity is borrowed (antibodies from the mother or an injected serum) and is short-lived.
- Edward Jenner pioneered vaccination against smallpox (1796); smallpox was declared eradicated by the WHO in 1980.
- India's Universal Immunisation Programme covers diseases such as tuberculosis (BCG), polio, diphtheria, pertussis, tetanus, measles, and hepatitis B.
- COVID-19 vaccines introduced new platforms in India, including Covaxin (inactivated virus) and Covishield (viral vector); verify the latest approved vaccines.
Vaccines, the active-versus-passive immunity distinction, Jenner and smallpox eradication, and India's immunisation schemes are recurring health and current-affairs items.
Active immunity (own antibodies, long-lasting, from vaccine or infection) versus passive immunity (ready-made antibodies, short-term). A vaccine is preventive; an antibiotic treats bacterial infection after it occurs.
Vaccines train the immune system to make antibodies; active immunity is long-lasting, passive immunity is borrowed and short-lived.