Rotaviruses were discovered in the 1970s. Since then doctors and scientists have shown that they are a problem to children all over the world. More than 500,000 children die from rotavirus infection each year and almost two million more become severely ill. The Bill & Melinda Gates Foundation are helping to pay for rotavirus vaccines in countries that cannot afford to buy them. Between 2006 and 2011 he gave more than 82 million US dollars.