Immunization exemptions in Michigan, 2005-2006 and 2006-2007 school years

Learning Objectives for this Presentation:
By the end of the presentation participants will be able to describe patterns in immunization exemptions in Michigan kindergartners and 6th graders.

Background:
In 2005, Michigan schools began reporting exemptions for individual students by type (medical, religious, or philosophical) and immunization using the Michigan Care Improvement Registry (MCIR). Before 2005, only aggregated information was reported, and it was unknown which immunizations were exempted. Exemption reporting by public and private schools is required by Michigan law.

Objectives:
Determine from exemptions by county, grade, and immunization: 1) number of exempted children; 2) most frequently exempted immunizations; 3) how exemption differs in association with other factors.

Methods:
For kindergartners and 6th graders, immunization exemptions for DTaP, polio, MMR, hepatitis B, and varicella vaccines reported via the MCIR were examined for school years 2005-2006 and 2006-2007.

Results:
In both school years, ~3.1% of 6th graders were exempt from at least 1 vaccine. In 2005-2006 and 2006-2007 respectively, ~3.0% and ~4.4% of kindergartners were exempt from at least 1 vaccine. During both school years, ~65% of exempted 6th graders were exempt from 1 vaccine only, while ~45% of exempted kindergartners were exempt from 1 vaccine only. About 20% and 25%, respectively, of exempted 6th graders and kindergartners refused all 5 vaccines. Exemptions were evenly distributed by vaccine type, although 6th graders were more often exempt from varicella, and kindergartners were less often exempt from hepatitis B. About 65% of exempted children had exclusively philosophical exemptions.

Conclusions:
Concern about high exemption rates may be overstated, since about half of all exempted students studied were exempt from 1 vaccine only. It is unclear why more kindergartners were exempted in 2006-2007 than 2005-2006, although one reason might be the new reporting method in 2005-2006.