Missed Opportunities for Influenza Vaccination in Children With Chronic Medical Conditions
Authors: Bailey Sally Joo 
Published: September 2006

Purpose of the Study.
To assess the frequency and characteristics of missed opportunities for influenza immunization in children with chronic medical conditions, and among unimmunized children in that group, to explore parent-reported reasons for not vaccinating their child.

Study Population.
A cohort of 926 children (aged 6 to 72 months) who were identified from October 1, 2002, through January 31, 2003, as having ≥1 high-risk conditions (HRCs). A total of 594 (64%) were male, and 734 (79%) were between 24 and 72 months of age. The children were insured privately (84%) or publicly (12%) or uninsured (3%). Diagnoses included asthma only (89%), cardiac conditions (3%), immunosuppressive conditions or therapies (2%), chronic nonasthma pulmonary conditions (2%), and other HRCs (2%).

Methods.
Data were obtained from shared billing and immunization registry databases of 4 private pediatric practices in metropolitan Denver, Colorado, during the 2002–2003 influenza season. Study sites had 5 to 8 pediatricians and 2 to 6 nonphysician providers per practice. The method of HRC identification through billing data using set diagnostic codes was documented to have a sensitivity of 72%, specificity of 95%, and an overall accuracy of 90% compared with medical charts. The billing system contained data for individual patient demographics, diagnostic codes, procedural codes for immunizations, and type of visit distinguished as well-child care (WCC) visit or not (non-WCC visit). Telephone surveys of randomly selected parents of children not given influenza vaccine were conducted in April to May 2003.

Results.
In children with asthma only (820), of all vaccine-eligible visits (881), 78% resulted in missed opportunities. Missed opportunities occurred at 62% of WCC visits and 86% of non-WCC visits (difference of 24%; 95% confidence interval: 16%–31%). The rate of influenza immunization was 43% among subjects with vaccine-eligible WCC visits compared with 18% for those without a vaccine-eligible WCC visit. In children with other HRCs (106), the rates of missed opportunities were similar to those children with asthma only. The rate of influenza immunization was also similar at 40% with vaccine-eligible WCC visits; however, the rate of immunization for those without a vaccine-eligible WCC visit was higher at 28%. If the subjects were immunized at their first opportunity, similar rates of immunization (61% for those with asthma vs 62% for those with other HRCs) would have been achieved. Telephone interviews with parents revealed lack of physician recommendation, low perceived susceptibility to influenza, and misconception of the risks of vaccination as the primary reasons.

Conclusions.
Missed opportunities for influenza immunization are common among children with asthma and other HRCs, particularly at non-WCC visits and later in the influenza season, and contribute to the persistently low influenza-immunization rate in this population.

Reviewer Comments.
As illustrated in this study, parents often rely on their child’s heath care provider to advise them about preventive health care measures. Therefore, it is important for providers to identify the patients at risk (existence of HRC), recognize the indications for influenza immunization, and discuss the pros and cons of influenza immunization with the parents and patients.