One of the most dramatic improvements in infant health has been related to widespread immunization of infants and children to the major communicable childhood diseases, including diphtheria, pertussis, tetanus, polio, measles, mumps, rubella, hepatitis, and Haemophilus influenzae type B infection. Immunizations to these infectious diseases have greatly reduced
morbidity and mortality in infants and young children. These immunizations are given at standard times as part of health promotion in infants and children. However, immunization programs have not completely eradicated these diseases, but have only lowered their prevalence. Immunization programs are effective only if all children receive the immunizations. Although most immunizations can be received through local health departments at no or low cost, many infants or young children do not routinely receive immunizations or do not receive the full regimen of immunizations. Methods to improve compliance and access to immunizations are needed. Immunization recommendations are subject to change as research leads to development of improved vaccines or more understanding of the microorganisms.
In summary, infancy is defined as that period from birth to 18 months of age. During this time, growth and development are ongoing. The relative immaturity of many of the organ systems places the infant at risk for a variety of illnesses. Birth initiates many changes in the organ systems as a means of adjusting to postnatal life. The birth process is a critical event, and maladjustments and injuries during the birth process are a major cause of death or disability. Premature delivery is a significant health problem in the United States. The premature infant is at risk for numerous health problems because of the interruption of intrauterine growth and immaturity of organ systems
