Promoting the use of influenza vaccine for children at risk of complications

Introduction
Influenza virus infections represent the most important cause of acute respiratory illness requiring medical attention beyond infancy. In an 8-year study in Houston, Texas, it was shown that half of school children under 17 years of age were infected each year with influenza virus. In preschool children the infection rate was about 30% each year.[1,2]

The complications of influenza generally result from damage to the respiratory epithelium, with secondary bacterial infection. In community studies, the incidence of otitis media following influenza is about 10% and approximately 7% for pneumonia.[3] While anyone can develop complications with influenza, some individuals are at increased risk of doing so because of pre-existing medical conditions.

Most obvious are underlying problems with the lungs such as cystic fibrosis, bronchopulmonary dysplasia, or troublesome asthma. Certain heart problems increase the risk of lung complications, particularly when heart function cannot meet the demands of normal activities. People with immune system impairment from chronic illness or medications are more likely to develop complications. Metabolic problems may be exacerbated by the stresses of influenza illness, diabetes mellitus being the prime example. Children with severe neurologic or neuromuscular conditions may have difficulty coping with respiratory conditions like influenza.

The influenza vaccine has proved to be safe and effective in children and is recommended for those predisposed to complications by underlying conditions (see Table 1). Despite this, it is the most poorly utilized vaccine in pediatrics. Recent surveys showed only 10% to 15% uptake among children and adults at high risk.[3,4]

Promotional program
The objective of our promotional program was to increase the use of influenza vaccine among children at risk of influenza complications.

BC’s Children’s Hospital provides tertiary care for a population of about 805,000 children. Many of those at risk of influenza complications are registered with the hospital’s subspecialty clinics. For the first year of our advocacy program we targeted patients with diabetes, asthma, or bronchopulmonary dysplasia. Both the cystic fibrosis and HIV clinics already had established influenza vaccine programs with uptake rates exceeding 90%.

Clinic directors identified patients meeting selection criteria. Information packages addressing the child’s disease in relation to influenza infection and vaccination were developed for parents and their health-care providers. In September 1998 these packages were mailed with a covering letter from the appropriate clinic director recommending vaccination of the at-risk child and household members. Patients were advised to seek vaccination from either their family physician or local health region office. Uptake was assessed from parents’ reply cards or telephone interviews in December or later.

Results
Among the 676 diabetics who received our package and supplied information on vaccination, 51.3% received influenza vaccine in 1998, a 19.4% increase over the 1997 season. Among the 325 asthmatics assessed, the uptake of influenza vaccine in 1998 was 51%, an increase of 20.6% over the 1997 season. Among the 87 bronchopulmonary dysplasia children assessed, the uptake of influenza vaccine in 1998 was 82.8%.

Fifty of these children were 18 months or older and thus were eligible for influenza vaccine in 1997. Their uptake in the 1998 season was 78%, an increase of 38% over the 1997 season. In both the asthmatic and diabetic groups older adolescents (>15 years of age) had a lower uptake of influenza vaccine (42% to 44%) in the 1998 season. The uptake of influenza vaccine for household members in 1998 was 42.2% for diabetics and 46.7% for asthmatics. In bronchopulmonary dysplasia households the uptake was 73.6%.

Conclusion
Educational efforts directed at groups at high risk of complications from influenza appear to be effective when they address the specific issues surrounding the child’s disease, are endorsed by a familiar specialist, and when the family physician is included in the educational process. The next goals of this advocacy program include expanding to other subspecialty clinics at BC’s Children’s Hospital, determining efficient means of reminding parents and patients of the annual need for influenza vaccine, and continuing to increase the uptake rates over the rates achieved in 1998.

A particular challenge will be determining effective means of communicating with adolescents at risk, who in this program consistently had lower influenza vaccination uptake rates. When the key program elements have been identified we will help other BC clinics implement their own influenza advocacy programs. With the threat of an influenza pandemic looming, one of the best preparations is to ensure that people at greatest risk from infection are participating in annual prevention programs.

Mrs Gordean Bjornson is a research associate with the Vaccine Evaluation Centre located at BC’s Children’s Hospital (BCCH). Dr David Scheifele is the director of the Vaccine Evaluation Center, professor of pediatrics, and an infectious disease specialist. Dr Daniel Metzger is a clinical assistant professor of pediatrics with the Diabetes Unit at BCCH. Dr Alexander Ferguson is head of the Allergy Clinic and professor of pediatrics at BCCH. Dr David Wensley is division head of Critical Care, and clinical professor of pediatrics at BCCH. Dr Michael Whitfield is associate professor of pediatrics and head of the Neonatal Follow-up Clinic at BCCH.