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Since the adoption of mass vaccination programs, many diseases have been curbed. [[Smallpox]], a contagious disease that killed 30 percent of those it infected, has been entirely eliminated through vaccination, excepting some strains maintained in labs for research purposes. Responsible for an estimated 300 to 500 million deaths worldwide in the 20th century, vaccination programs of the 19th and 20th century were effective at curbing the disease, and in 1979 the World Health Organization declared smallpox to be eradicated.<ref>https://www.cdc.gov/smallpox/history/history.html</ref>

Since the adoption of mass vaccination programs, many diseases have been curbed. [[Smallpox]], a contagious disease that killed 30 percent of those it infected, has been entirely eliminated through vaccination, excepting some strains maintained in labs for research purposes. Responsible for an estimated 300 to 500 million deaths worldwide in the 20th century, vaccination programs of the 19th and 20th century were effective at curbing the disease, and in 1979 the World Health Organization declared smallpox to be eradicated.<ref>https://www.cdc.gov/smallpox/history/history.html</ref>

Another disease that has been eliminated from the US is [[Polio]], which killed over 3,000 people in the United States in 1952, <ref>http://www.cdc.gov/nchs/data/vsus/VSUS_1952_2.pdf</ref> and afflicted such noted persons as President [[Franklin Delano Roosevelt]], actor Alan Alda, and musician Itzak Perlman. When doctors began using a vaccine to fight polio, it practically eradicated the disease in the developed world.

Another disease that has been eliminated from the US is [[Polio]], which killed over 3,000 people in the United States in 1952,<ref>http://www.cdc.gov/nchs/data/vsus/VSUS_1952_2.pdf</ref> and afflicted such noted persons as President [[Franklin Delano Roosevelt]], actor Alan Alda, and musician Itzak Perlman. When doctors began using a vaccine to fight polio, it practically eradicated the disease in the developed world.

The incidence of other diseases such as [[diphtheria]], [[pertussis]], and [[measles]], has decreased greatly since the invention of vaccines against these diseases.<ref>https://www.unicef.org/pon96/hevaccin.htm</ref>

The incidence of other diseases such as [[diphtheria]], [[pertussis]], and [[measles]], has decreased greatly since the invention of vaccines against these diseases.<ref>https://www.unicef.org/pon96/hevaccin.htm</ref>