OVERVIEW OF THE IMMUNE SYSTEM
LYMPHATIC AND IMMUNE SYSTEM
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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so many people are immune that the virus can’t spread
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so many people are immune that the virus spreads more quickly to those that are susceptible
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so many people are immune that the virus becomes resistant to the vaccination
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the virus kills everyone except those that are immune, making the entire remaining population immune to it
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Detailed explanation-1: -’Herd immunity’, also known as ‘population immunity’, is the indirect protection from an infectious disease that happens when a population is immune either through vaccination or immunity developed through previous infection.
Detailed explanation-2: -Herd immunity occurs when the majority of a population is immune to a disease or virus. Otherwise known as community immunity 1, it helps to slow the spread of infectious diseases in two ways : People contract the disease and develop an immune response. People are vaccinated.
Detailed explanation-3: -Herd immunity occurs when a large portion of a community (the herd) becomes immune to a disease. The spread of disease from person to person becomes unlikely when herd immunity is achieved.
Detailed explanation-4: -The more infectious a disease, the greater the population immunity needed to ensure herd immunity. For example, measles is highly contagious and one person with measles can infect up to 18 other people. This means that around 95% of people need to be immune in order for the wider group to have herd immunity.
Detailed explanation-5: -Herd effect can be measured by quantifying the decline in incidence in the unimmunised segment of a population in which an immunisation programme is instituted. Herd immunity applies to immunisation or infection, human to human transmitted or otherwise.