National Immunization Survey
The National Immunization Survey (NIS) is sponsored by the National Center for Immunizations and Respiratory Diseases (NCIRD) and conducted jointly by NICRD and the National Center for Health Statistics (NCHS), Centers for Disease Control and Prevention. The NIS is a list-assisted random-digit-dialing telephone survey followed by a mailed survey to children's immunization providers. The survey began data collection in April 1994 to monitor childhood immunization coverage. The target population for the NIS is children between the ages of 19 and 35 months living in the United States at the time of the interview. Data from the NIS are used to produce timely estimates of vaccination coverage rates for all childhood vaccinations recommended by the Advisory Committee on Immunization Practices (ACIP). Estimates are produced for the nation and non-overlapping geographic areas consisting of the 50 states, the District of Columbia, and selected large urban areas. The official estimates of vaccination coverage rates from the NIS are rates of being up-to-date with respect to the ACIP recommended numbers of doses of vaccines.
The NIS study has two parts:
(1) A household telephone survey. This survey asks questions about childhood immunization for children 19-35 months of age and requests parental permission for contacting children's vaccination providers. Data are used primarily to monitor immunization coverage in the preschool population in non-overlapping geographic areas.
(2) A survey of vaccination providers. This survey of doctors and other vaccination providers is conducted for study participants who have provided consent for this phase of the study.
During 2011, the response rate was 61.7% for the landline telephone sample and 25.2% for the cellular telephone sample. Providers returned adequate vaccination rates for 71.6% of children with completed household interviews, for a total of 19,534 children with provider-reported vaccination records included in this report; 17,309 from the landline sampling frame and 2,225 from the cellular telephone sampling frame.