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What is Protective value of vaccine is 95%. It means and explain in detail?
Vaccine is an immuno-biological substance designed to produce specific protection against a given disease It stimulates the production of protective antibody and other immune mechanisms Vaccines can be prepared from live modified organisms, inactivated or killed organisms, extracted cellular fractions, toxoids or combination of these Vaccine efficacy is the percentage reduction of disease in a vaccinated group of people compared to an unvaccinated group, using the most orable conditions Vaccine efficacy was designed and calculated by Greenwood and Yule in 1915 for the cholera and typhoid vaccines It is best measured using double- blind, randomized, clinical controlled trials, such that it is studied under "best case scenarios Ref : Park&;s Textbook of Preventive and Social Medicine; 23rd edition