Statewide Pandemic Influenza Vaccination Reminders for Children with Chronic Conditions

Objectives: We evaluated the use of a statewide immunization information system (IIS) to target influenza vaccine reminders to high-risk children during a pandemic.

Methods: We used Michigan's IIS to identify high-risk children (i.e., those with ≥ 1 chronic condition) aged 6 months to 18 years with no record of pH1N1 vaccination among children currently or previously enrolled in Medicaid (n = 202,133). Reminders were mailed on December 7, 2009. We retrospectively assessed children's eligibility for evaluation and compared influenza vaccination rates across 3 groups on the basis of their high-risk and reminder status.

Results: Of the children sent reminders, 53,516 were ineligible. Of the remaining 148,617 children, vaccination rates were higher among the 142,383 high-risk children receiving reminders than among the 6234 high-risk children with undeliverable reminders and the 142,383 control group children without chronic conditions who were not sent reminders.

Conclusions: Midseason reminders to parents of unvaccinated high-risk children with current or past Medicaid enrollment were associated with increased pH1N1 and seasonal influenza vaccination rates. Future initiatives should consider strategies to expand targeting of high-risk groups and improve IIS reporting during pandemic events.