Diphtheria once was a major cause of illness and death among children. The U.S. recorded 206,000 cases of diphtheria in 1921, resulting in 15,520 deaths. Before there was treatment for diphtheria, up to half of the people who got the disease died from it.
Starting in the 1920s, diphtheria rates dropped quickly in the U.S. and other countries that began widely vaccinating. In the past decade, there were less than five cases of diphtheria in the U.S. reported to the CDC. However, the disease continues to play a role globally. In 2011, 4,887 cases of diphtheria were reported to the World Health Organization (WHO), but there are likely many more cases.