Public health efforts eradicated smallpox from the globe in the late 1970s. The last naturally occurring case was in Somalia in 1977 (followed by a couple of lab accident cases in 1978). Public health set its sites on Polio next- with an expectation that it could be eradicated before the turn of the century. A series of naturally occurring and man made setbacks slowed the progress. The world has been struggling to eradicate polio for the last few decades.
Since 1988 about 2.5 billion children around the globe have been vaccinated against polio, and the number of polio cases per year has decreased by 99%. The world was on the verge of eliminating polio in the 2000s, but political strife and other issues in West Africa turned the tide and set the eradication clock back. The good news is that the world is making progress again. The list of countries where polio cases is shrinking, as are the number of cases. Parts of Nigeria, India, and parts of Afghanistan and Pakistan account for more than 75% of global cases. A large scale vaccination effort is just finishing in India as part of an urgent response to confirmation of a new case in North India and more than 1.8 million children under 5 were immunized. The Bill and Melinda Gates Foundation has been adding support to the new push to eradicate by working with the Global Polio Eradication Initiative. The goal is to eradicate polio by 2015.
Polio is more challenging to eradicate than smallpox was because it’s spread through what public health calls the “fecal-oral” route (i.e. sewage) rather than person to person, which means that public health needs to use mass vaccination efforts in areas with cases rather than the more focused (and less labor intensive) “ring vaccination” approach used to eradicate smallpox.