The number of reported cases of vaccine-preventable diseases has generally decreased over the past several decades. In 2005, there were no reported cases of diphtheria in the entire U.S. population, and no cases of tetanus or polio among children under 5 years of age. Only one case of rubella was reported among children under 5 years of age, the first to be reported in this age group since 2001.
From 2004 to 2005, the number of reported cases of measles, mumps, and hepatitis A and B decreased among children under 5 years of age. Rates of hepatitis B infection have declined 98 percent among children under 13 years of age since 1990, with the implementation of a national strategy to eliminate the disease. This strategy includes routine screening of pregnant women for the hepatitis B virus and routine vaccination of infants and children. It is important to note that since most hepatitis B infections among infants and young children are asymptomatic, the reported number of cases likely underestimates the incidence in these age groups. The overall incidence of Hepatitis A has also dropped dramatically since routine vaccination for children living in high-risk areas was recommended starting in 1996.
While the number of reported cases of several vaccine-preventable diseases decreased from 2004 to 2005, the number of reported cases of H. Influenzae, rubella, and pertussis, increased over the same period. In 2005, the incidence of reported pertussis among the entire U.S. population (8.7 per 100,000 people) increased just slightly after doubling from 2003 to 2004. This rate was highest among children under 6 months of age who were too young to have received the first three doses of acellular pertussis vaccine. This age group accounted for 13 percent of all reported pertussis cases in 2005.