What Is a Vaccine? By Vincent Iannelli, MD / December 24, 2018 / active immunity, adjuvants, antigens, Edward Jenner, eradicated diseases, herd immunity, incubation period, live vaccines, passive immunity, placebos, quarantines, saline placebo, shedding, titer testing, titers, vaccine definitions, vaccine glossary, vaccinia, variolation A vaccine stimulates your immune system, providing active immunity and protecting you from disease. Share this:TweetPrintEmailShare on TumblrWhatsAppLike this:Like Loading...