Vaccine-preventable respiratory infections in childhood.

In the past decade, immunization rates among preschool-age children in the United States have decreased to levels lower than those in many developing countries. As a result, epidemics of vaccine-preventable diseases have occurred, especially in urban areas. Six of the infections prevented by immunization--those caused by Bordetella pertussis, Streptococcus pneumoniae, Haemophilus influenzae type B, Corynebacterium diphtheriae, measles virus, and influenza virus--frequently cause respiratory tract disease. Pneumonia in children may have subtle presentations and require special considerations depending on the age and condition of the child and the current rate of disease in the community. In addition to the epidemics occurring throughout the country, the growing number of immunocompromised children has also influenced diagnostic, treatment, and prevention considerations. These patients include children with cancer, organ transplants, congenital immune disorders, sickle cell disease, human immunodeficiency virus infection, as well as other disorders that lead to increased risk of infection. The current recommendations for routine and special childhood immunizations are reviewed in this article.