Elderly people are advised to get influenza (flu) vaccinations every year. Each year, a different ty

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Elderly people are advised to get influenza (flu) vaccinations every year. Each year, a different type of flu vaccine has to be made. This is because\

Professor PC Thomas Classes · Answer

(d) : Flu virus makes small errors due to mutations when it copies its genetic code during reproduction. But it lacks the ability to repair those errors, because it is a RNA virus and RNA, unlike DNA, lacks a self-correcting mechanism. As a result, flu virus is not genetically stable. Every generation is slightly different, and those differences accumulate as time passes. This slow deviation is called antigenic drift, and it is the reason why it is necessary to reformulate flu vaccines every year. Every flu season, the genetic make-up of the dominant strains from the prior year will have drifted, changing the surface structure of those strains just enough to diminish, or even destroy, the effectiveness of the previous year's vaccine.