Explain how a vaccine provides immunity against infection. What problems are associated with the use of a?

live attenuated vaccine? Many infectious diseases have no effective vaccines-what might be the reason(s) for this?

1 Answer

  • 7 years ago
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    Cassie - an effective vaccine contains a modified virus or bacterial substance that will result in a person's developing immunity against getting a severe disease. Particles from the infectious material are treated and weakened or killed before being made into a vaccine. These particles are called antigens. Hopefully injected antigens will cause the body to develop antibodies against a severe infection or maybe prevent that infection altogether if the person later gets exposed to the dangerous infectious virus or bacteria. "Attenuated" vaccines do contain live infectious agents that have been greatly weakened (attenuated) and may cause a mild for of the infection which allows the body to develop protective antibodies without getting a severe illness. New vaccines are constantly being developed. Right now being tested are new vaccines against malaria and hepatitis C. It's a matter of trying to make and successfully test new vaccines = an effort that can take many, many years. Patience, patients!

    Source(s): a physician
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