School-age children in the developing world are heavily affected by worm infestation and nutritional deficiencies such as iron, iodine and vitamin A.  In most of the countries where SC works, the majority of the school population has intestinal worms, which alongside poor diets, cause nutritional deficiencies like anemia. These infections and nutritional deficiencies cause children to become increasingly stunted throughout their school years, and can inhibit their ability to learn by reducing attention span and causing absenteeism.  Malaria, in countries with a high prevalence, can account for 10-20 percent of mortality and 50 percent of absenteeism among school-age children. Healthier children stay in school longer, attend more regularly, learn more and become healthier and more productive adults.