Definition of "vaccine" []

• A preparation of a weakened or killed pathogen, such as a bacterium or virus, or of a portion of the pathogen's structure that upon administration stimulates antibody production or cellular immunity against the pathogen but is incapable of causing severe infection. (noun)
• A preparation from the cowpox virus that protects against smallpox. (noun)
• Computer Science A software program designed to detect and stop the progress of computer viruses. (noun)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "* obama: h1n1 vaccine 'strongly recommended'* pregnant women express fears over swine flu vaccine* cdc warns neurologists to watch for nerve disease after shots* h1n1 unlikely to mutate into' superbug ': US study* swine flu won't be as dangerous as we thought, uk official says* pfizer agrees record fraud fine* envirohealth: intl paper treads monsanto's path to' frankenforests'* more geo-engineering: can man-made 'volcanoes' slow down climate change?"
• "But now the vaccine is almost here, the question is, “Do you want it?”"
• "Immunity from legal suits in this case means if the vaccine is a suspected cause of death or injury, the law will not allow victims to sue the vaccine manufacturer."