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According to the Centers for Disease Control and Prevention's Vaccine Glossary, '''Active immunity''' is "the production of antibodies against a specific [[disease]] by the [[immune system]]. Active immunity can be acquired in two ways, either by contracting the disease or through [[vaccination]].  

According to the [[Centers for Disease Control and Prevention]]'s Vaccine Glossary, '''active immunity''' is "the production of antibodies against a specific [[disease]] by the [[immune system]]. Active immunity can be acquired in two ways, either by contracting the disease or through [[vaccination]].  

Active immunity is usually permanent, meaning an individual is protected from the disease for the duration of their lives."<ref>http://www.cdc.gov/vaccines/about/terms/glossary.htm#a</ref>

Active immunity is usually permanent, meaning an individual is protected from the disease for the duration of their lives."<ref>http://www.cdc.gov/vaccines/about/terms/glossary.htm#a</ref>