National Immunization Survey
The National Immunization Survey (NIS) is a continuing nationwide telephone sample survey to monitor vaccination coverage rates among children 19-35 months of age and among teenagers 13-17 years of age.
NHIs is a nationwide telephone sample survey of households with age-eligible children and teenagers. NIS uses a two-phase sample design. First, a random-digit-dialing sample of telephone numbers is drawn. When households with age-eligible children are contacted, the interviewer collects information on the vaccinations received by all age-eligible children and obtains permission to contact the children's vaccination provider. In the second phase, identified providers are sent vaccination history questionnaires by mail. Providers' responses are compared with information obtained from households to provide a more accurate estimate of vaccination coverage levels. Final estimates are adjusted for households without telephones and for nonresponse.