The vaccine is a biological preparation used to strengthen and increase immunity against a specific virus, where the body is injected with the same type of virus or bacteria in order to attack the immunity and create antibodies when infected with the virus, there are viruses that threaten that virus and defeat it easily, so the ideal vaccine is the one that has the ability to confront this Viruses so that when they are present in the body again, the body's immunity can fight them. Examples of these vaccines are the flu vaccine, quadriplegia, and measles.
