Immunization Index | Data and Statistics
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
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.
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.
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).
15-23 months of age |
2-4 years of age | 5-6 years of age | 7 years and older | |||||
---|---|---|---|---|---|---|---|---|
2000-2001 Daycare Report |
2000-2001 Validation Survey |
2000-2001 Daycare Report |
2000-2001 Validation Survey |
2000-2001 Daycare Report |
2000-2001 Validation Survey |
2000-2001 Daycare Report |
2000-2001 Validation Survey |
|
Number of Daycare Sites Included |
21 |
21 | 33 | 33 | 33 | 33 | 33 | 33 |
Number of Children Enrolled | 239 | 235 | 1753 | 1642 | 771 | 772 | 376 | 332 |
Number of Children Examined | - | 235* | - | 1642* | 772* | 332* | ||
Number of Children Adequately Immunized |
168 |
187 79.6% |
1416 80.8% |
1390 84.7% |
428 55.5% |
696 90.2% |
308 81.9% |
311 93.7% |
* Standardized sampling techniques were followed for reviewing records at centers with > 100 enrolled students.
15-23 months | 2 years to Kindergarten | Kindergarten and older | ||||
---|---|---|---|---|---|---|
2000-2001 Head Start Report | 2000-2001 Validation Survey | 2000-2001 Head Start Report | 2000-2001 Validation Survey | 2000-2001 Head Start Report | 2000-2001 Validation Survey | |
Number of Head Start Sites Included | - | - | 46 | 46 | - | - |
Number of Children Enrolled | - | - | 4041 | 4237 | - | - |
Number of Children Examined | - | - | - | 3962* | - | - |
Number of Children Adequately Immunized | - | - | 3646 (90.2%) |
3748 (94.6%) |
- | - |
* 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.
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.