The Immune System

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…The process of inducing an immune response is called immunization. It may be either natural, through infection by a pathogen, or artificial, through the use of serums or vaccines. The immune system cannot protect the body from diseases by itself. Sometimes it needs help. Physicians give their patients vaccines to help protect them from certain severe, life-threatening infections. Vaccines and serums boost the body's ability to defend itself against particular types of viruses or bacteria.