Comparison of NIS and NHIS/NIPRCS vaccination coverage estimates. National Immunization Survey. National Health Interview Survey/National Immunization Provider Record Check Study.

BACKGROUND: The National Immunization Survey (NIS) and the National Health Interview Survey (NHIS) produce national coverage estimates for children aged 19 months to 35 months. The NIS is a cost-effective, random-digit-dialing telephone survey that produces national and state-level vaccination coverage estimates. The National Immunization Provider Record Check Study (NIPRCS) is conducted in conjunction with the annual NHIS, which is a face-to-face household survey. As the NIS is a telephone survey, potential coverage bias exists as the survey excludes children living in nontelephone households. METHODS: To assess the validity of estimates of vaccine coverage from the NIS, we compared 1995 and 1996 NIS national estimates with results from the NHIS/NIPRCS for the same years. RESULTS: Both the NIS and the NHIS/NIPRCS produce similar results. CONCLUSION: The NHIS/NIPRCS supports the findings of the NIS.

Vaccination visits in early childhood: just one more visit to be fully vaccinated.

BACKGROUND: This study characterizes the healthcare visits at which children receive vaccinations, including the number of these visits and the number of vaccinations that are administered. METHODS: The 1999 National Immunization Survey (NIS) is a nationally representative sample of children aged 19 to 35 months, verified by provider records, that is conducted to obtain estimates of vaccination coverage rates. We describe the number of healthcare visits in which one or more vaccinations were given, the number of vaccinations given at these visits, and the number of visits and vaccinations needed for an underimmunized child to complete the recommended vaccination series. RESULTS: Of the children who did not receive all doses of the recommended vaccinations (4:3:1:3:3 vaccination series), three fourths had four or more immunization visits. Vaccination coverage increased as the number of visits increased, and children who had completed the series were more likely to receive multiple vaccinations than those who had not. Most children (70.7%) received a maximum of four vaccinations in any immunization visit. The majority of children (73.5%) who had not completed the 4:3:1:3:3 vaccination series needed only a single visit to complete the series. The majority (61.7%) of children who needed only one visit also needed only one additional vaccination. CONCLUSIONS: While estimated national coverage for all recommended vaccinations is considerably below the Healthy People 2000 and Healthy People 2010 goal of 90%, achieving this goal is in essence just one visit away. If all children who needed one more visit were to receive that final visit, the national coverage among children 19 to 35 months for all recommended vaccinations would be 93%.

Vaccination status of children living in rural areas in the United States: are they protected?

OBJECTIVE: To estimate the vaccination coverage levels of children living in rural areas and identify statistically significant differences in coverage between children living in rural areas and their suburban and urban counterparts. METHODS: Children aged 19 to 35 months participating in the 1999 National Immunization Survey (NIS) were included in the study. Children were classified as living in a rural, urban, or suburban area based on their telephone exchange (area code plus the first three digits of the telephone number). Statistically significant differences in vaccination coverage levels between the rural population and their urban counterparts were determined for individual vaccines and vaccine series. RESULTS: Overall, 18% of the children included in the 1999 NIS lived in a rural area, 46% lived in a suburban area, and 36% lived in an urban area. The characteristics of the rural population were: 72% were white, non-Hispanic; 24% were below the poverty level; 16% had a mother with <12 years of education; and 30% received vaccinations from a public provider. Eighty percent of rural children, 79% of suburban children, and 77% of urban children completed the 4:3:1:3 series. The rural population had statistically significantly lower (p<0.01) varicella coverage levels than their suburban and urban counterparts. CONCLUSION: Results of this study suggest that children living in rural areas are just as likely to receive the basic 4:3:1:3 vaccination series as their suburban and urban counterparts. Uptake of the varicella vaccine appears to be slower in rural areas than urban areas. Further studies are recommended to identify the risk factors for not receiving the varicella vaccine in rural areas.

The impact of record scattering on the measurement of immunization coverage.

BACKGROUND: Lack of a consolidated immunization record may lead to problems with determining individual immunization needs at office visits as well as measuring vaccination coverage levels of a clinician's practice or a community's population. OBJECTIVES: For children with multiple immunization providers, evaluate the difference in coverage levels using data from all responding immunization providers compared with: 1) the most recent immunization provider's records, 2) the first immunization provider's records, and 3) a randomly selected immunization provider's records. Identify characteristics of the most recent provider that may be associated with reporting incomplete immunization histories. METHODS: Data from the 1995 National Immunization Provider Record Check Study (NIPRCS) were used for analysis. The NIPRCS is a provider validation study of the household reported immunization histories of all children 19 to 35 months of age included in the National Health Interview Survey (NHIS). Providers identified by the child's parent during the NHIS interview are mailed a 2-page survey to report all immunizations (type and date) the child received, regardless of the provider who administered the shots, and child's first and most recent visit dates to the practice. RESULTS: Of the 1352 children with provider data, 304 (22%) had received immunizations from more than one provider. Compared with information from all providers and depending on the vaccine, the most recent provider records underestimated coverage by 9.6 to 13.4 percentage points; the initial provider records underestimated coverage by 15.6 to 34.6 percentage points; and the randomly selected provider records underestimated coverage by 10.0 to 20.7 percentage points. Public facilities and having an immunization summary sheet in the patient's chart were associated with having complete records. CONCLUSION: Scattered immunization records significantly compromise the ability of clinicians to determine the immunization status of their patients who received immunizations at other sites of health care. Routinely assessing immunization coverage levels at the practice level, implementing a recall system, and developing community-wide immunization registries are some strategies to reduce the problem of scattered immunization records.immunization, assessment, provider validation, record scattering.

National, state, and urban area vaccination coverage levels among children aged 19-35 months--United States, 1998.

PROBLEM/CONDITION: High vaccination levels in the population are necessary to decrease disease transmission and prevent disease; therefore, an important component of the U.S. vaccination program is the assessment of vaccination coverage. Current goals are for > or = 90% coverage with recommended vaccines during the first 2 years of life. REPORTING PERIOD: January-December 1998. DESCRIPTION OF SYSTEMS: The National Immunization Survey (NIS) is an ongoing, random-digit-dialed telephone survey that gathers vaccination coverage data for children aged 19-35 months in all 50 states and 28 urban areas. Vaccination coverage rates derived from NIS data are adjusted statistically for households with multiple telephone lines, household nonresponse, the proportion of households without telephones, and vaccination provider nonresponse. The results were also adjusted to match the known total population of children in each survey area. RESULTS: On the basis of NIS data, national coverage was > or = 90% for three doses of poliovirus vaccine (Polio), three doses of Haemophilus influenzae type b vaccine (Hib), and one dose of measles-containing vaccine (MCV). Coverage was the highest ever reported for four doses of any diphtheria and tetanus toxoids and pertussis vaccine (DTP) (i.e., diphtheria and tetanus toxoids and pertussis vaccine, diphtheria and tetanus toxoids [DT], or diphtheria and tetanus toxoids and acellular pertussis vaccine [DTaP]) (83.9%), three doses of hepatitis B vaccine (Hep B, 87.0%), and one dose of varicella vaccine (43.2%). The number of states achieving the > or = 90% goal was 47 for three doses of Hib, 40 for three doses of Polio, 40 for one dose of MCV, nine for three doses of Hep B, and seven for four doses of DTP. Proportionally fewer urban areas achieved the > or = 90% goal: 23 of 28 for three doses of Hib, 13 for three doses of Polio, 16 for one dose of MCV, five for three doses of Hep B, and one for four doses of DTP. No state or urban area has yet achieved the > or = 90% goal for varicella. INTERPRETATION: Findings from the 1998 NIS indicate that national vaccination coverage levels for routinely recommended childhood vaccines are at the highest levels ever reported. However, substantial variation in coverage remains at the state and urban area levels. PUBLIC HEALTH ACTIONS: The public health community and vaccination providers in areas with low coverage should intensify their efforts to implement recommended strategies for increasing vaccination coverage to ensure that children are equally well protected throughout the United States.

Assessing immunization performance of private practitioners in Maine: impact of the assessment, feedback, incentives, and exchange strategy.

INTRODUCTION: A provider-based vaccination strategy that has strong supportive evidence of efficacy at raising immunization coverage level is known as Assessment, Feedback, Incentives, and Exchange. The Maine Immunization Program, and the Maine Chapter of the American Academy of Pediatrics collaborated on the implementation and evaluation of this strategy among private providers. METHODS: Between November 1994 and June 1996, the Maine Immunization Program conducted baseline immunization assessments of all private practices administering childhood vaccines to children 24 to 35 months of age. Coverage level assessments were conducted using the Clinic Assessment Software Application. Follow-up assessments were among the largest practices, delivering 80% of all vaccines. RESULTS: Of the 231 practices, 58 were pediatric and 149 were family practices. The median up-to-date vaccination coverages among all providers for 3 doses of diphtheria-tetanus-pertussis vaccine and 2 doses of oral polio vaccine, and 4 doses of diphtheria-tetanus-pertussis vaccine, 3 doses of oral polio vaccine, and 1 dose of measles-mumps-rubella vaccine at age 12 and 24 months were 90% and 78%, respectively, and did not vary by number of providers in a practice or by specialty. Urban practices had higher coverage than rural practices at 12 months (92% vs 88%). The median up-to-date coverage for 4 doses of diphtheria-tetanus-pertussis vaccine, 3 doses of oral polio vaccine, and 1 dose of measles-mumps-rubella vaccine at 24 months of age improved significantly among those practices assessed 1 year later (from 78% at baseline to 87% at the second assessment). On average, the assessments required 21/2 person-days of effort. CONCLUSIONS: We document the feasibility and impact of a public/private partnership to improve immunization delivery on a statewide basis. IMPLICATIONS: Other states should consider using public/private partnerships to conduct private practice assessments. More cost-effective methods of assessing immunization coverage levels in private practices are needed.

Immunization performance measurement in a changing immunization environment.

OBJECTIVE: The measurement of performance in the delivery of recommended vaccinations for children is used frequently as a marker for quality of care and as an outcome for studies of interventions to improve immunization coverage levels. The critical element of immunization performance measurement is the determination of immunization status. This methodologic review 1) discusses immunization status as a measure of quality of primary care for children, 2) describes immunization status measures used in immunization intervention studies, and 3) examines selected technical issues of immunization status measurement. METHODS AND TOPICS: 1) Description of the characteristics of immunization status measurements obtained by a systematic review of studies published between 1980 and 1997 on interventions to raise immunization coverage, and 2) illustration of technical considerations for immunization status measurement using one local database and one national database of immunization histories. Technical issues for immunization status measurement include 1) the need to use documented immunization histories rather than parental recall to determine immunization status, 2) the need to link records across providers to obtain complete records, 3) the sensitivity of immunization status to missing immunization data, and 4) the potential of measures incorporating combinations of immunizations to underestimate the degree of vaccination in a population. CONCLUSIONS: Immunization performance measurement has many characteristics of a robust quality of care measure, including high acceptance by primary care providers of routine vaccination, association of immunization status with the conduct of other clinical preventive services, agreed-on technical and programmatic standards of care, and legislative requirements for medical record documentation. However, it is not without challenges. Careful attention to technical issues has potential to improve immunization delivery health services research.