The burden of influenza illness in children with asthma and other chronic medical conditions.

OBJECTIVE: Although influenza immunization is recommended for children with high-risk medical conditions, the majority of such children do not receive influenza vaccine. This study was designed to measure the burden of influenza among children with asthma and other chronic medical conditions. STUDY DESIGN: We performed a retrospective cohort study of children younger than 15 years with medically treated asthma or other chronic medical conditions enrolled in the Tennessee Medicaid program from 1973 to 1993. We determined rates of hospitalization for acute cardiopulmonary disease, outpatient visits, and antibiotic courses throughout the year. Annual differences between event rates when influenza virus was circulating and event rates during winter months when there was no influenza in the community were used to calculate influenza-attributable morbidity. RESULTS: Influenza accounted for an average of 19, 8, and 2 excess hospitalizations for cardiopulmonary disease yearly per 1000 high-risk children aged <1 year, 1 to <3 years, and 3 to <15 years, respectively. For every 1000 children, an estimated 120 to 200 outpatient visits and 65 to 140 antibiotic courses were attributable to influenza annually. CONCLUSIONS: Children younger than 15 years with asthma and other chronic medical conditions experience substantial morbidity requiring inpatient and outpatient care during influenza season. More effective targeting of this population for annual influenza immunization is warranted.

Rates of hospitalization for respiratory syncytial virus infection among children in medicaid.

OBJECTIVE: To determine rates of hospitalization associated with respiratory syncytial virus (RSV) infection among children with and without specific medical conditions. STUDY DESIGN: Retrospective cohort study of all children <3 years old enrolled in the Tennessee Medicaid program from July 1989 through June 1993 (248,652 child-years). RESULTS: During the first year of life, the estimated number of RSV hospitalizations per 1000 children was 388 for those with bronchopulmonary dysplasia, 92 for those with congenital heart disease, 70 for children born at < or = 28 weeks' gestation, 66 for those born at 29 to <33 weeks, 57 for those born at 33 to <36 weeks, and 30 for children born at term with no underlying medical condition. In the second year of life, children with bronchopulmonary dysplasia had an estimated 73 RSV hospitalizations per 1000 children, whereas those with congenital heart disease had 18 and those with prematurity 16 per 1000. Overall, 53% of RSV hospitalizations occurred in healthy children born at term. CONCLUSIONS: Children with bronchopulmonary dysplasia have high rates of RSV hospitalization until 24 months of age. In contrast, after the first year of life, children with congenital heart disease or prematurity have rates no higher than that of children at low risk who are <12 months old.