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World Health Organization (WHO) on Twitter: "#Polio cases worldwide: 1988: 350000 2016: 27 That's a ⬇ of more than 99.9% #VaccinesWork! Let's #EndPolio #WorldPolioDay https://t.co/bvvHTOFA7b" / Twitter
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Two New Polio Cases In Nigeria Are The First Detected In Africa In More Than Two Years : Goats and Soda : NPR
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Evolving epidemiology of poliovirus serotype 2 following withdrawal of the serotype 2 oral poliovirus vaccine | Science
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