Explanation: Vaccines are shots of medicine that are used to prevent someone from catching a strain or virus. They are used worldwide, and are given to mostly children and elderly, to protect their immune systems.
What is the history of vaccines? The first vaccine was developed in 1796 by Edward Jenner. He made it to find a cure to smallpox. He tested it on a 13-year-old infected with smallpox, and the boy later showed immunity to smallpox. In 1798, the smallpox vaccine was first released to the public.
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