Microsoft's Bill Gates, one of the world's richest men and highest profile aid donors, gives to a child a rotavirus vaccine against diarrhea at the Ahentia Health Centre, in Awutu Senya district, in the Central Region of Ghana, on March 26, 2013. Gates is in Ghana to meet with government and health officials on ways to combat global health problems. The Bill Gates Foundation donates at least five percent of its assets each year to fight Polio Myelitis, HIV/AIDS, Tuberculosis, Malaria and other infectious diseases across the globe. AFP PHOTO/PUIS UTOMI EKPEI        (Photo credit should read PIUS UTOMI EKPEI/AFP/Getty Images)