National Immunization Survey (NIS)

Beginning in 1994, NIS has collected information about the immunization coverage of children 19 months to 35 months of age.  Beginning in 2008, information has also been collected about adolescents, 13-17 years of age, across the United States.  Data are used to monitor immunization coverage in the preschool population in 78 non-overlapping geographic areas.  The survey is a collaborative effort between CDC, the National Center of Health Statistics and the  National Center for Immunization and Respiratory Diseases.  More information regarding the NIS can be found at

How accurate and reliable are these numbers?

The NIS is accurate and reliable.  The accuracy is supported by the agreement between the NIS, a telephone survey, and the National Health Interview survey, a nationally representative, household, door-to-door survey. The reliability of the NIS is reflected in the size of the confidence interval; it is more reliable at the national level than at the state or urban level.  This is because the number of interviews overall is so much larger than the number of interviews for any state.

Why do the NIS vaccination coverage rates differ from other surveys?

There are many possible reasons why the rates could differ, because the systems use:

  • Different age ranges (19-35 months, 24-35 months);
  • Different computation rules (all doses, only age-appropriate doses);
  • Different sampling methods (population vs. provider vs. registry based);
  • Different numbers of participants;
  • Incomplete records (missing doses given by different providers);
  • Different vaccine combinations (e.g. 431331 or 4313314).

Additional NIS data are available at the CDC’s ChildVaxView web site:

Summary of NIS Data

Click here for a pdf summary of the Virginia and National 4314314 Rates, 2015-2020
Click here for a pdf summary of Single Antigen Coverage Rates, 2015-2020
Click here for a pdf summary of Virginia Single Antigen Data, 2015-2020

Click here for a pdf summary of Vaccination Coverage in Adolescents, 2019-2022