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Since doctors began using vaccines, however, many diseases have been curbed. [[Polio]], for example, killed over 3,000 people in the United States in 1952 [http://www.http://www.cdc.gov/nchs/data/vsus/VSUS_1952_2.pdf], and inflicted 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 erradicated the disease in the developed world.  

Since doctors began using vaccines, however, many diseases have been curbed. [[Polio]], for example, killed over 3,000 people in the United States in 1952 [http://www.http://www.cdc.gov/nchs/data/vsus/VSUS_1952_2.pdf], and inflicted 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 erradicated the disease in the developed world.  

Other diseases that have been curbed since the invention of vaccines include [[smallpox]] (previously a yearly killer of thousands worldwide), [[chicken pox]], [[measles]], [[mumps]], [[rubella]], and [[typhoid]]. Because these diseases were prevalent before the use of vaccines and rare afterwards, many people believe that vaccines may have something to do with preventing the diseases, although correlation does not always necessarily imply causation.

Other diseases that have been curbed since the invention of vaccines include [[smallpox]] (previously a yearly killer of thousands worldwide), [[chicken pox]], [[measles]], [[mumps]], [[rubella]], and [[typhoid]].

==References==

==References==