Immunization Index  |  Data and Statistics

Daycare and Head Start
Immunization Validation Survey

Results of the 2000-2001
Daycare and Head Start Validation

Immunization Program
Indiana State Department of Health
2 North Meridian
Indianapolis, IN 46204
Published: 07/2001

Indiana State Department of Health
Gregory A. Wilson, M.D., State Health Commissioner
Mary DePrez, Deputy State Health Commissioner

Public Health Services Commission
Joni Albright, M.P.A., Assistant Commissioner

Immunization Program
Michael Runau, M.S., Program Director

Primary Author
Geoff Prysak, M.P.H., Epidemiologist

Preface

Each year, according to Indiana Code 12-17.5-2-5, Indiana child care centers must submit an annual report to the Indiana State Department of Health (ISDH) demonstrating compliance with immunization requirements for their enrolled children. To verify the reports that these centers send to ISDH are accurate, the Immunization program biennially conducts a validation survey on a random sample of Daycare and Head Start centers throughout Indiana. The results of the Daycare and Head Start validation survey for the 2000-2001 school year are found in this report.
 

Methods

A random sample of child care centers was selected from the 426 Daycare and 162 Head Start sites listed in the Immunization Programs Daycare and Head Start database. This sampling was conducted according to procedures developed by the Assessment Branch of the National Immunization Program at CDC. Factors involved in this sampling include: total number of enrolled children, approximate immunization coverage levels, and acceptable level of error in sampling. Using this methodology, 33 Daycare centers and 46 Head Start sites were selected for a validation of the coverage levels found in their 2000-2001 immunization report.

ISDH immunization field representatives reviewed records for the up-to-date status of attendees at each of the 33 Daycare centers and 46 Head Start sites selected for validation. Complete immunization levels for each site were then calculated and compared with the sites reported immunization coverage level for the 2000-2001 reporting year. These comparisons were made for overall coverage levels at each center, as well as coverage levels for children in each of the age categories required in the reports; Daycare centers compared children 15 23 months of age, 2 4 years of age, 5 6 years of age, and 7 years and above, while Head Start centers compared children 2 years of age to kindergarten, since they only enroll children in this age category.

Results

The 2000-2001 Daycare and Head Start validation survey found that a majority of child care centers accurately report the immunization coverage levels of children enrolled in their sites ( 10% difference between reported rate and validated rate). The median change in coverage between the validation survey and a centers self-reported coverage was 8.5% for Daycare centers and 1.3% for Head Start centers statewide. Individually, the validation survey found that 3.0% of Daycare centers and 17.0% of Head Start sites had no change in the overall coverage levels reported in their 2000-2001 annual immunization report. The majority, 63.6%, of Daycare centers and 60.9% of Head Start sites were found to have higher immunization coverage levels in the validation survey than in their reported levels. The minority, 33.3%, of Daycare sites and 21.7% of Head Start sites had immunization rates that were lower upon validation when compared to those that were initially reported by each site (Figure 1).
  

Figure 1. Percent change between validation surveys and Daycare and Head Start
annual reports, 2000-2001 Indiana immunization validation survey.

 
Aggregate analysis of child-specific data found that overall immunization coverage levels at the time of the validation survey were significantly higher than those reported by the child care centers in their 2000-2001 report (p < 0.05). More specific analysis revealed that immunization coverage levels at the time of the validation were higher than the rates reported by the child care centers for every age category (Table 1).
 

* Standardized sampling techniques were followed for reviewing records at centers with > 100 enrolled students.

* Standardized sampling techniques were followed for reviewing records at centers with > 100 enrolled students.
Head Start centers only enroll children between two years of age and pre-kindergarten.

Discussion

Validation of self-reported immunization coverage levels is an important role of the ISDH immunization program. Although child care centers have consistently reported relatively high immunization coverage levels in recent years, validating these reports is an essential means of ensuring that the quality of reporting is maintained.

The findings of the validation report suggest that child care centers underreport their immunization rates. Overall, child care center validation rates are fairly close to their self-reported immunization rates, but the site-specific and age-specific analyses reveal that the validation rates are higher. This underreporting may be due to several factors, including the highly variable nature of child care center enrollment, the lag time between reporting and validation that allows for the children to get caught up with their immunizations, and the child care center administrators completing the forms incorrectly. Incorrectly filling out the forms most certainly has led to a major discrepancy for the 5-6 year old Daycare category (55.5% versus 90.2%, self-report versus validation, respectively). When the 5-6 year old category figures are combined with the 2-4 year old category figures (as was done in the past to form a 2 year old to kindergarten category), the totals make more sense (73.1% versus 86.4%, self-report versus validation, respectively). This 13% difference is small enough that it may be explained by other reasons. In the future, an educational campaign may be necessary to teach child care center administrators how to properly fill out the self-report forms.

Another important issue is the over-reporting of immunization coverage levels. Eleven-percent of the child care centers had greater than a 10% decrease in their immunization coverage levels between the validation survey and the immunization self-report. One potential reason the validation survey had lower levels could be due to the fact that some children may have received invalid doses (i.e., not having appropriate intervals between doses of vaccine). Such invalid doses may have been included in a centers immunization report but would not have been counted when validated by an immunization field representative. This situation is similar to the underreporting issue, which is most likely due to the centers inaccurate completion of their immunization reports, leading to either artificially high or low reported immunization coverage levels for their center.

Regardless of any fluctuation, Daycare and Head Start centers that strongly enforce the state immunization requirements would be expected to have consistently high immunization coverage levels. Child care centers in Indiana are attempting to comply with Indiana state immunization laws, which is evident by 68.4% (54/79) of child care centers exhibiting validation rates > 90.0%. While this represents a majority, ALL child care centers must implement and strictly enforce immunization policies to prevent the outbreak of vaccine-preventable diseases among their enrollees. Failure to do so not only violates state law, but also unnecessarily places susceptible children at risk for contracting an otherwise preventable disease.

Immunization Index  |  Data and Statistics