Assessing the Relationship between Seasonal and H1N1 Influenza Vaccination Status in Michigan Children, 2009–2010

Abstract

OBJECTIVES To examine the relationship between the outcome of vaccination for H1N1 influenza and receipt of seasonal influenza vaccine in Michigan children during the 2009-2010 season, we examined the influenza vaccination status of all Michigan residents aged six months to 18 years who were enrolled in the Michigan Care Improvement Registry. We calculated descriptive statistics for dichotomous and categorical variables, including numbers of children vaccinated with either influenza (H1N1) monovalent vaccine and/or seasonal influenza vaccine, gender, race! / ethnicity, provider type, moved-or-gone-elsewhere (MOGE) status, and vaccin type. We used logistic regression, adjusting for potential confounders and effect modifiers (age and MOGE status), to calculate odds ratios associate with H1N1 vaccine status (vaccinated vs. unvaccinated). RESULTS. Michigan children who were vaccinated for seasonal influenza from August 1, 2009, to February 27, 2010, were 6.26 (95% confidence interval 6.18, 6.34) times as likely as children who were unvaccinated for seasonal influenza to be vaccinated with H1N1 2009 monovalent vaccine. Private health-care providers administered 91% of the seasonal influenza vaccine and 59% of the H1N1 vaccine. CONCLUSIONS. Increasing seasonal influenza vaccination campaign efforts could also benefit pandemic influenza vaccination efforts. Special educational outreach to parents regarding the importance of influenza vaccination for all children, regardless of age, may be needed. Stocking and offering traditional seasonal vaccine with pandemic-specific vaccine may aid in increasing immunization uptake. Efforts should be made to ensure that private providers are supplied with adequate pandemic vaccine as part of preparedness planning.