Immunization Coverage Among Children 19-35 Months and 3-6 Years of Age with Sickle Cell Disease, Michigan

Background: Children with sickle cell disease (SCD) are at increased risk of acquiring invasive infections. Timely and complete immunization coverage could reduce the number and burden of these invasive infections.

Objectives: Determine what proportion of children with SCD in Michigan receive appropriate immunizations in a timely manner

Methods: Newborn screening (NBS) records for all children born from 2004-2008 confirmed with SCD or trait (SCT) were linked with live birth certificates. Through live births, NBS data were linked with the Michigan Care Improvement Registry (MCIR), a statewide web-based system where all immunizations of Michigan residents are reported. Immunization data were retrieved for children aged 19-35 months and 3-6 years with SCD or SCT. We further compared that data with immunization data among all children 19-35 months and 3-6 years old in Michigan. The following vaccines, known as the 4:3:1:3:3:1:4 series, were considered: DTaP/DT/DTP, Polio, MMR, Hib, Hepatitis B, Varicella, and PCV 7/13.

Results: Of 14,811 newborns diagnosed with SCD or SCT through NBS from 2004-2008, approximately 97% of them were linked with live births, and immunization data were available for 90%. For children with SCD, the completion rate for the 4:3:1:3:3:1:4 series, was 66.0% among those 19-35 months and 71.3% among those 3-6 years of age. Children aged 19-35 months with SCD had slightly higher immunization completion rates compared to those with SCT and statewide. For children aged 3-6 years, the completion rates were similar across all 3 groups.

Conclusions: Immunization coverage rates for children with SCD should be improved at younger ages given their risks for infections. Through the linkages between NBS, live births, and immunization data, we will monitor immunization coverage among children with SCD and provide feedback to providers and families. An educational flyer was developed to alert SCD patient advocates and families about the need for immunizations, particularly PCV13.