Immunization and vaccine-preventable illness, United States, 1992 to 1997.

In contrast to the 1980s, immunization rates increased dramatically in the United States in the mid-1990s. Three-quarters of all 2-year-olds had received all recommended immunizations in 1997 as compared to just over one-half in 1992. Immunization rates for individual vaccines have reached 90 percent for three of the vaccines--measles, mumps, rubella; pollo; and Haemophilus influenzae type b (Hib). The vaccine for diphtheria, tetanus and pertussis, however, and the newer vaccine for hepatitis B have not yet reached 90 percent of 2-year-olds. The rising immunization levels in young children have resulted in declining incidence of almost all of the vaccine-preventable illnesses. Cases of measles and Hib have declined 95 percent and the incidence of rubella and congenital rubella, hepatitis B and mumps has also declined. Pertussis (whooping cough), however, continued its pattern of periodic increases and decreases. This lack of improvement is probably due to a combination of lower immunization levels for pertussis and waning immunity in previously immunized adolescents and young adults. Federal efforts such as the President's Childhood Immunization Initiative along with its Vaccines for Children program have been credited for a great deal of this improvement. These programs increased public awareness of the need for and access to immunizations, better tracking of immunizations and vaccine-preventable illnesses and have also removed cost barriers to receipt of such protection. At the same time, new vaccines (against chickenpox and rotavirus) and safer versions of older vaccines (pertussis) have been brought into widespread use. Children can now be vaccinated against increasing varieties of childhood diseases. While progress in immunization has been good, areas in need of improvement remain. Pertussis continues to be a problem both in terms of incidence and immunization levels. Also, immunization levels differ significantly by poverty level and race and ethnicity. Black, Hisparic, American Indian and Asian children are less likely to be fully immunized than non-Hispanic white children and poor children are less likely to be fully immunized than nonpoor children.