10. Resulting in the deaths of between 5 to 10 percent of those infected, diphtheria had been nearly eradicated in the developed world until opposition to vaccinations allowed the condition to survive into the 21st century
A bacterial infection, diphtheria is a highly contagious condition spread between humans through the air, direct contact, and even via contaminated objects. With symptoms beginning gradually two to five days after infection, starting with a sore throat and fever, diphtheria, if left untreated, can result in a blockage growing in the throat, kidney failure, and heart problems. Unlike many harmful illnesses, prior exposure to diphtheria does not preclude future recurrences. Appearing throughout modern history, with Spain suffering an epidemic in 1613 and New England in 1735, in 1878 Queen Victoria’s daughter, Prince Alice, in addition to her own daughter Princess Marie, died from diphtheria.
During the 1910s, spurred by rising death tolls, a vaccine was discovered after a mass public appeal. Nonetheless, in the 1920s more than 200,000 cases resulting in 15,000 deaths per year were still reported in the United States. However, despite a prolonged period of sustained decline, due to increasing opposition by parents to vaccination diphtheria is beginning to make a comeback. In 2015, Spain saw the first case of diphtheria since 1986, with fatal instances also appearing in Venezuela, Belgium, and Indonesia. In 2011, more than 5,000 cases of diphtheria were diagnosed globally, with an average fatality rate of between 5 to 10 percent.