National Immunization Survey

The National Immunization Survey (NIS) began collecting data in 1994 for the purpose of establishing estimates of up-to-date immunization levels in each state, the District of Columbia, and 27 large urban areas. The NIS is conducted by the National Opinion Research Center for the Centers for Disease Control and Prevention; it is jointly sponsored by the National Immunization Program and the National Center for Health Statistics. Children between the ages of 19 and 35 months living in the United States at the time of the survey are the target population for the NIS: Data about their immunizations are collected from a parent or other adult from the child's household who is knowledgeable about their immunization record. If possible, this information is confirmed with the child's immunization providers.

The vaccinations included in the NIS are those recommended by the Advisory Committee on Immunization Practices, which are currently 4 doses of diphtheria, tetanus, and acellular pertussus vaccine (DTaP); 3 doses of polio vaccine; 1 dose of measles/mumps/rubella (MMR) vaccine; Haemophilus influenzae Type β vaccine (Hib); hepatitis A vaccine (Hep A); 3 doses of hepatitis B vaccine (Hep B); 1 dose of varicella zoster vaccine (chicken pox); 4 doses of pneumococcal conjugate vaccine (PCV); and influenza vaccine. Hepatitis A is recommended only in selected states with a high incidence of the disease. All vaccines except varicella, influenza, and pneumococcal have been included in the NIS since its inception: Pneumococcal was added in 2002, and influenza and hepatitis A were added in 2003.

The NIS collects data in two ways: through telephone interviews with households selected through random-digit dialing and through a mail survey of physicians and other vaccination providers; the latter is called the Provider Record Check Study. The telephone interview collects information from parents of eligible children about the immunizations each child has received, the dates of the immunizations, and the demographic and socioeconomic information about the household. If the parent grants permission, the child's vaccination providers are contacted to verify the child's vaccination record. The state and local estimates of vaccination coverage are calculated every quarter using NIS data and are used to evaluate progress toward national and local immunization goals. The coverage for series of vaccines is also reported, including the 4:3:1:3:3 series (4 + DTaP, 3 + polio, 1 + MMR, 3 + Hib, and 3 + Hep B).