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Vaccines and immunisation

New vaccines, the campaigns that deliver them, and the alliances that fund vaccines for the world. Prelims has asked about COVID-19 vaccine platforms and why pneumococcal conjugate vaccines matter for India.

Foundation note: The immunisation programme and how vaccines are made

mRNA vaccine: A vaccine that delivers genetic instructions for a pathogen's protein, so the body's cells make it and train the immune system without live virus.

Viral vector vaccine: A vaccine that uses a harmless modified virus to carry a gene for the pathogen's protein into cells, which then make it.

Serotype: A variant within a microbial species, told apart by its surface antigens; immunity to one serotype need not protect against another.

Reverse vaccinology: Designing a vaccine by searching a pathogen's genome for proteins suitable to build it on.

adjuvant: A substance added to a vaccine to strengthen and lengthen the immune response to its main ingredient.

Human papillomavirus: A common sexually transmitted virus, whose high risk types cause cervical cancer where the infection persists.

Antibody dependent enhancement: Low levels of cross reactive antibodies worsening a new dengue infection instead of blocking it.

Tetravalent vaccine: A vaccine against all four serotypes.