Researchers have found a more effective polio vaccine--a double strain known as a bivalent vaccine--than the previously used monovalent and trivalent vaccines. Roland Sutter and his colleagues conducted the bivalent study in India in 2008, and the work has been published in Lancet.
According to the International Business Times the vaccine is being used in India, Afghanistan and Nigeria with a 90 percent reduction in polio cases.
Although polio vaccines have been commonplace in the U.S. for more than half a century, some major countries, including India, continue to struggle with the paralyzing disease. Currently, polio is endemic in four countries, down from 125 in 1988, when more than 1,000 children were paralyzed daily, according to the WHO.