How a Vaccine Trains the Body

Written by Studio AM.

The immune system protects the body against infection. Some of its cells can remember features of a germ they have encountered, helping them respond more quickly during a later exposure.

Vaccines build on this ability. Depending on the type, a vaccine may contain weakened or inactive germs, selected parts of a germ, or instructions that let our cells make a target the immune system can recognize. This is a kind of preview: a controlled introduction that helps the body prepare its defenses. Memory cells can remain after the initial response.

If a matching germ later invades, the immune system may respond more effectively. Protection takes time to develop, and some vaccines require several doses or later boosters. Vaccination can reduce the risk of illness or severe disease, but it does not guarantee that every infection will be prevented.

A sore arm or a mild fever can occur after vaccination, and serious reactions are rare. The suitable vaccine and schedule depend on the person and disease. The purpose is to prepare immune defenses with much less risk than the diseases vaccines help prevent.

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  1. Question 1 of 4

    The passage mainly explains

  2. Question 2 of 4

    What may a vaccine provide, depending on its type?

  3. Question 3 of 4

    Why may the body respond more effectively to a later matching germ?

  4. Question 4 of 4

    In this passage, 'preview' most nearly means

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