National Immunization Survey Data Research Articles

Vaccination coverage among young homeless children compared to US national immunization survey data

IntroductionComprehensive vaccination coverage among homeless children in the United States (US) is largely unknown although a few studies suggest low coverage with single vaccinations. This study compared vaccination coverage with a combined 7-vaccines series among homeless children in the District of Columbia (DC) to coverage among other US children. Materials and methodsA cross-sectional survey of homeless children in DC was conducted from 2018 to 2019. Recruitment occurred at housing shelters, social services centers, and a diaper dispensary, and through limited chain referral. English-speaking parents of a child aged 19 to 35 months who spent the majority of the last 30 nights homeless were recruited. Participants consented for their child’s healthcare providers to submit vaccination records. The vaccination coverage estimate of this sample was compared with estimates of three populations in the 2018 National Immunization Survey (NIS): children in DC (NIS DC), children in the US (NIS US), and children in the US below the federal poverty level (NIS poor). ResultsMost of the 135 children had experienced at least two lifetime episodes (63.7%) and 12 months (57%) of homelessness. The estimated percent up to date was 52.6% (95% CI: 43.8%, 61.3%). This estimate was 20.4 (95% CI: 11.9, 28.8, p < .0001), 20 (95% CI: 11.5, 28.4, p < .0001), and 11.5 (95% CI: 3.1, 20, p < .01) percentage points lower than estimates for the NIS DC, NIS US and NIS poor populations, respectively. After adjusting for child’s age and race/ethnicity, vaccination coverage of the NIS DC sample was below that of NIS US (p < .01) and NIS poor samples (p < .05). ConclusionChildren experiencing homelessness may be at risk of under-vaccination, even when compared to a general population of children in poverty. Awareness of this heightened risk may allow for more precise targeting of vaccination delivery support specifically to children experiencing homelessness.

Increasing the Precision of Estimates of Immunization Coverage Among 19- to 35-Month-Old Children in the United States

The National Immunization Survey (NIS) is the United States’ primary tool for assessing immunization coverage among 19- to 35-monthold children. Although annual estimates from the NIS are quite precise at the national level, US State-level estimates have much larger sampling error than national-level estimates. We combined two independent unbiased estimates of US State-level coverages within a given year to obtain new estimates which are more precise than previously published estimates. We first calculated a model-based estimate for each State for 2001 using multiple years of NIS data. Next, we combined each model-based estimate with the corresponding, previously reported NIS estimate for 2001. Our resulting estimates of State-level immunization coverage had smaller standard errors than the previously published estimates. To make similar improvements in precision by increasing sample size would, depending on State, require an increase in sample size of 30% – 120%.

Addressing Parental Vaccine Hesitancy towards Childhood Vaccines in the United States: A Systematic Literature Review of Communication Interventions and Strategies.

Parental vaccine hesitancy is becoming an increasingly important public health concern in the United States. In March 2020, an assessment of the latest CDC National Immunization Survey data found that more than one-third of U.S. children between the ages of 19 and 35 months were not following the recommended early childhood immunization schedule. Furthermore, a 2019 national survey found that approximately 1 in 4 parents reported serious concerns towards vaccinating their children. Vaccine hesitancy is now associated with a decrease in vaccine coverage and an increase in vaccine-preventable disease outbreaks and epidemics in the United States. Many studies have focused on understanding and defining the new socio-medical term, vaccine hesitancy; few have attempted to summarize past and current health communication interventions and strategies that have been successful or unsuccessful in tackling this growing phenomenon. This systematic literature review will attempt to aid public health professionals with a catalogue of health communication interventions and strategies to ultimately address and prevent parental vaccine hesitancy in the long term. Out of 1239 search results, a total of 75 articles were included for analysis, ranging from systematic reviews, quantitative surveys, and experimental designs to ethnographic and qualitative studies. For the presentation of results, a taxonomy was used to organize communication interventions according to their intended purpose. The catalogue of interventions was further broken down into specific components and themes that were identified in the literature as essential to either the success or failure in preventing and addressing parental vaccine hesitancy towards childhood vaccines.

Missed opportunities for simultaneous administration of the fourth dose of DTaP among children in the United States

BackgroundSimultaneous administration of all age-appropriate doses of vaccines is an effective strategy for raising vaccination coverage. Vaccination coverage for ≥4 dose of DTaP (diphtheria, tetanus toxoids, and acellular pertussis vaccine) among children 19–35months in the United States has not reached the Healthy People 2020 target of 90%. Risk factors for missed opportunities for simultaneous administration of the fourth dose of DTaP have not been investigated. MethodsA missed opportunity for simultaneous administration of the fourth dose of DTaP is defined as the failure to administer an age-eligible fourth dose of DTaP, and during the same age-eligible period for the fourth dose of DTaP other recommended and age-appropriate doses of vaccines are given to children. This study used 2001–2014 National Immunization Survey data to describe the trend in missed opportunities for simultaneous administration of the fourth dose of DTaP from 2001 through 2014, assess the prevalence of children who missed opportunities for simultaneous administration of the fourth dose of DTaP by selected factors, and recognize significant risk factors for missed opportunities for simultaneous administration of the fourth dose of DTaP. ResultsFrom 2001 to 2014, the prevalence of missed opportunities for simultaneous administration of the fourth dose of DTaP among children 19–35months in the United States ranged from 5.7% to 9.0%; across 13 factors considered, the prevalence of missed opportunities varied from 3.3% to 22.9%. Children who were late in receiving the first to third dose of DTaP had significantly higher prevalence of missed opportunities for simultaneous administration of the fourth dose of DTaP than children who received these doses on-time, with adjusted prevalence ratios for late vs. on-time of 1.7, 1.6, and 3.2, and all P-value<0.01. ConclusionsImproving on-time vaccination of the third dose of DTaP could substantially reduce missed opportunities for simultaneous administration of the fourth dose of DTaP.

Status of Breastfeeding and Child Immunization Outcomes in Clients of the Nurse-Family Partnership.

Background The Nurse-Family Partnership (NFP) is a home visiting program serving first-time, low-income mothers, with an area of focus on healthy early childhood development. Previous foundational trials of program effect on breastfeeding and immunizations have shown a mix of neutral and positive results. The present evaluation investigates these effects following program scale-up, using a large contemporary cohort of clients. Methods Nurse-Family Partnership client breastfeeding and immunization status were compared to National Survey of Children's Health data and National Immunization Survey data, respectively. Sample differences in demographic covariates were adjusted using logistic regression. Results Nurse-Family Partnership clients were significantly more likely to have ever breastfed (adjusted prevalence ratio [aPR: 1.20 (1.17, 1.23)] and maintain breastfeeding at 6 [aPR: 1.17 (1.10, 1.24)] and 12 [aPR: 1.39 (1.25, 1.53)] months, but less likely to exclusively breastfeed at 6months [aPR: 0.84 (0.70, 0.95)] NFP clients were significantly more likely to be up-to-date on immunizations at 6 [aPR: 1.23 (1.22, 1.25)], 18 [aPR: 1.33 (1.30,1.35)], and 24 [aPR: 1.15 (1.14, 1.16)] months of age than the reference cohort, with no significant difference at 12months. Discussion Nurse-Family Partnership clients had more beneficial breastfeeding and immunization outcomes than children of mothers with demographically similar profiles. However, exclusive breastfeeding at 6months lags behind the reference sample and represents a potential area for further improvement.

Vaccine Timeliness: A Cost Analysis of the Potential Implications of Delayed Pertussis Vaccination in the US.

Pertussis infection remains an important public health problem, particularly in infants. Despite high coverage, pertussis vaccination delays can leave infants at a vulnerable age with less protection than anticipated. Current diphtheria-tetanus-pertussis (DTaP) vaccination timeliness for the first 3 doses in the US was estimated using National Immunization Survey data. A Markov model estimated the potential impact on outcomes and costs of a hypothetical situation of vaccination at exactly 60, 120 and 180 days, compared with current timeliness. Incidence and unit cost data came from published sources. Age-specific incidence (for month of life) of pertussis and the associated probabilities of hospitalization and death for the US, during 2000-2007, were taken from a recently published US DTaP vaccination cost-effectiveness study. The cost analysis was conducted from the healthcare system's perspective over a 1-year time horizon. A regression analysis was conducted to explore the factors associated with vaccination delay. Current DTaP vaccination was estimated to be delayed by 16, 27 and 44 days, for the first, second and third doses, respectively, relative to vaccination at exactly 60, 120 and 180 days. The model estimated that vaccination at exactly age 60, 120 and 180 days could prevent approximately 278 pertussis cases, 103 hospitalizations and 1 death in infants aged <1 year in the US, gaining approximately 38 quality-adjusted life years and saving approximately $1.03 million in healthcare costs. Timely administration of infant pertussis vaccine doses could potentially reduce subsequent pertussis cases, hospitalizations, deaths and medical costs in infants aged <1 year in the US.

Complete Influenza Vaccination Trends for Children Six to Twenty-Three Months.

Prevention of influenza among infants and young children is a public health priority because of their high risk for influenza-related complications. Depending on a child's age and previous influenza vaccination history, they are recommended to receive either 1 dose or 2 doses of influenza vaccine to be considered fully vaccinated against influenza for the season. We compared estimates of full (complete) influenza vaccination coverage of children 6 to 23 months across 10 consecutive influenza seasons (2002-2012), by race/ethnicity, age group, and by number of doses required to be fully vaccinated given child's vaccination history. National Immunization Survey data were used to estimate full influenza vaccination status among children 6 to 23 months on the basis of provider report. Estimates were computed by using Kaplan-Meier survival analysis methods. Full influenza vaccination coverage among children 6 to 23 months increased from 4.8% in the 2002-2003 influenza season to 44.7% in the 2011-2012 season. In all 10 influenza seasons studied, non-Hispanic black children and Hispanic children had lower full influenza vaccination coverage than non-Hispanic white children. For all 10 influenza seasons, full influenza vaccination coverage was higher among children requiring only 1 dose compared with those requiring 2 doses. Less than half of children 6 to 23 months in the United States, and an even a smaller percentage of Hispanic and non-Hispanic black children, are fully vaccinated against influenza. More implementation of evidence-based strategies that increase the percentage of children who are fully vaccinated is needed.

Adult Immunization 2012: Politics, Process, and Progress

In this issue, the ACIP presents the recommended Adult Immunization Schedule for 2012. The editorialist discusses the rationale behind key changes between this and previous ACIP recommendations.

Out-of-Pocket Costs of Childhood Immunizations: A Comparison by Type of Insurance Plan

The "Guide to Community Preventive Services" strongly recommends reducing out-of-pocket costs to increase vaccination rates among children. Nevertheless, out-of-pocket expenses are still incurred during the receipt of childhood vaccines, vaccine administration, and associated well-child visits. Our goal was to estimate total and out-of-pocket costs of childhood immunization. We used the 2003 benefit-plan data for all 1217 private and public health plans registered in Georgia and the 2003 Advisory Committee on Immunization Practices recommended vaccine schedule to calculate costs to vaccinate children aged 0 to 5 years in 2003 dollars. By applying published estimates of health insurance enrollment of Georgia children, we calculated the total and out-of-pocket costs per child according to insurance status and race/ethnicity. Immunization coverage according to payer type was based on National Immunization Survey data. Out-of-pocket costs ranged between $0 (Medicaid/Peachcare) and $652 (uninsured/Medicare). Most out-of-pocket costs were incurred during the first year of life. Up-to-date immunization status ranged from 63.7% for uninsured persons to 83.2% for privately insured persons. Up-to-date status was negatively correlated with out-of-pocket costs and the proportion of the population below 250% of the federal poverty level. For most Georgia families, out-of-pocket expenses for childhood immunizations were low, favoring compliance with the recommended immunization schedule. However, families least able to afford the expense faced disproportionately high out-of-pocket costs. Out-of-pocket costs were inversely correlated with immunization coverage levels. Uninsured children whose families lived below 250% of the federal poverty level experienced the lowest immunization coverage levels. Immunization coverage through the Vaccines for Children Program and Medicaid/State Children's Health Insurance Programs should be promoted to minimize or eliminate out-of-pocket costs related to childhood immunizations, especially among children of low-income families.

Maternal education, child immunizations, and public policy: Evidence from the US National Immunization Survey

This article measures the independent association of maternal education level and childhood immunization rates in the USA and compares the associations in states that provide free vaccines to all residents (Universal) and those that do not (non-Universal). To do this, the US-based National Immunization Survey data from 1995 to 2003 for children 19–35 months of age were analyzed. Unadjusted estimates of up-to-date status for the 4:3:1:3:3 series and the pneumococcal conjugate vaccine were estimated by the level of maternal education. Linear probability regressions produced adjusted estimates of maternal education effects controlling for covariates. Adjusting for race/ethnicity, income, and other covariates, children of mothers with less than high school education were found to be 7.8% ( p<0.05) less likely than children of mothers with college education to be up-to-date for the 4:3:1:3:3 vaccine series. For the newer pneumococcal conjugate vaccine, these children were 4.5% ( p<0.05) less likely to be up-to-date. Residence in a Universal state was found to significantly attenuate these effects. As such, higher maternal education, independent of income and race/ethnicity is associated with improved child immunization rates, but subsidizing immunization choices diminishes the disadvantage associated with lower maternal educational achievement.

Socioeconomic factors and persistent racial disparities in childhood vaccination.

To better understand the effects of socioeconomic factors on racial disparities in childhood vaccination. The National Immunization Survey data collected in 1999-2003 among children 19-35 months of age were analyzed using chisquare tests for trends and logistic regression modeling. Statistical significance was based on P<0.05. When adjusted by mother's education and household income, racial disparities in childhood vaccination were substantially reduced. The adjustment for mother's education reduced the disparity only slightly, but the adjustment for household income had the greater impact. Research should examine socioeconomic differences across populations to better understand racial disparities in health.

Assessment of Immunization Registry Databases as Supplemental Sources of Data to Improve Ascertainment of Vaccination Coverage Estimates in the National Immunization Survey

To evaluate the use of immunization registry data to supplement missing or incomplete vaccination data reported by immunization providers (referred to as "providers" hereafter) in the National Immunization Survey. Cross-sectional, random-digit-dialing, telephone survey to measure vaccination coverage among children aged 19 to 35 months in the United States. Four sites with mature (with >67% of provider participation in the area) immunization registries. Of the 639 children with complete household interviews, interviewers had consent from the respondents for 569 (89.0%) children to contact their providers and for 556 (87.0%) children to contact both providers and registries. Percentages of children up-to-date for vaccines based on data from providers, registries, and both sources combined. According to provider-reported data, weighted estimates of coverage for the recommended childhood vaccine series 4:3:1:3 at the 4 sites were 65.6%, 78.8%, 81.6%, and 77.0%. According to registry data, these coverage rates were consistently lower: 31.7% (P<.05), 65.4%, 71.9%, and 61.8%, respectively. When all unique vaccine doses were combined from both sources, the pooled 4:3:1:3 coverage rates increased to 72.0%, 92.0%, 88.7%, and 80.2%, respectively. The quality and completeness of vaccination histories from the registries were inconsistent and varied by sites. Vaccination coverage estimates were the lowest when only registry-reported data were used and were the highest when provider- and registry-reported histories were combined. Although registries enrolled and matched more children, vaccination histories were missing, incomplete, and inconsistent. The quality and completeness of the registry data must be improved and must be comparable across all states before further consideration may be given to supplement or replace the provider-reported National Immunization Survey data.

More About the Ross Mothers Survey

To the Editor .— The 2002 National Immunization Survey (NIS) provides important information on rates of breastfeeding, including exclusive breastfeeding in the United States.1 Another instrument, the Ross Laboratories Mothers Survey (RMS), is a long-standing survey that has been the basis for most of the national breastfeeding statistics cited over the years. Although both surveys provide information on national breastfeeding rates, there are a number of key differences of which readers should be aware that make direct comparisons between the 2 surveys very difficult. First, confusion may arise concerning the year of the NIS survey versus the years represented by the breastfeeding data reported. The NIS provided breastfeeding data that were collected over a 3-year period, from February 1999 to June 2001, because the NIS breastfeeding data were collected retrospectively, when children were 19 to 35 months of age. Thus, none of the 2002 NIS data actually reflected breastfeeding practices for the year 2002. In contrast, RMS data have been reported for the year in which the data were …

Ranking states' immunization coverage: an example from the National Immunization Survey

The National Immunization Survey (NIS) provides state-level estimates of preschool immunization coverage. These coverages are frequently presented in ranked lists, and ranks are frequently over-interpreted. In this paper, we highlight the difficulty in interpreting ranked point estimates. To demonstrate the uncertainty of ranks, parametric bootstrap methods were used to derive 90 per cent confidence intervals for ranks of state vaccination coverage levels among preschool children. We graphically compared states to a reference state. If NIS data are used to rank states, one should consider presenting confidence intervals for rank and the results of comparisons of one state with another graphically.

Prevalence of Breastfeeding in the United States: The 2001 National Immunization Survey

To address key gaps in the annual monitoring of breastfeeding prevalence in the United States, 3 breastfeeding questions concerning the initiation, duration, and exclusivity of breastfeeding were added to the rotating modules of the National Immunization Survey (NIS) beginning in the third quarter of 2001. The present study examines the current prevalence of breastfeeding in the United States using NIS data from this initial quarter. The NIS is a random-digit-dialing survey of households with children aged 19 to 35 months, followed by a mail survey of the eligible children's vaccination providers to validate the child's vaccination information. In the third quarter of 2001, a randomly selected subset of households interviewed in the NIS (N = 896) were asked questions about breastfeeding. Almost two thirds (65.1%) of children had ever been breastfed. At 6 and 12 months, 27.0% and 12.3%, respectively, were receiving some breast milk. Non-Hispanic blacks had the lowest rates of breastfeeding initiation and continuation. Exclusive breastfeeding rates were low in the United States with only 7.9% at 6 months. Although breastfeeding initiation is near the national goal of 75%, breastfeeding continuation lags behind the national goals of 50% and 25% at 6 and 12 months, respectively. Strenuous public health efforts are needed to improve breastfeeding practices among blacks.

The first oral rotavirus vaccine, 1998-1999: estimates of uptake from the National Immunization Survey.

On August 31, 1998, the rhesus-human reassortant rotavirus vaccine (RRV-TV) was licensed for use in the U.S. During the next nine months, 15 cases of intussusception were reported among infants who received the vaccine. Case-control and cohort studies showed a significantly increased risk of developing intussusception within one week of receiving the vaccine; subsequent ecologic studies did not. In this study, the authors used data on RRV-TV vaccination rates from the National Immunization Survey (NIS) to estimate state and national RRV-TV uptake rates and factors associated with receiving RRV-TV. These estimates are a key component in evaluating published ecologic studies designed to investigate the relationship between receipt of the vaccine and intussusception. The authors analyzed NIS data for children ages 19 to 35 months who were eligible to receive RRV-TV between September 1998 and July 1999. The authors estimated vaccine coverage and the number of doses administered by state, NIS sampling quarter, and birth cohort, and analyzed demographic and socioeconomic variables to evaluate their relationship with receiving RRV-TV. It was estimated that approximately 1 million doses of RRV-TV were administered to 504,585 (+/-61,854) children, 13.4% (+/-1.6%) of children who were eligible. The estimated number of doses administered and the vaccination coverage rate varied greatly from state to state. Children living in households with higher socioeconomic conditions were more likely to receive the vaccine. Ecologic studies had a limited ability to detect a significant increase in the population incidence rate of intussusception that could be attributed to RRV-TV because populations in these studies consisted primarily of children who did not receive the vaccine. The example from RRV-TV demonstrates some of the challenges of assessing the magnitude of the association between a vaccine and an uncommon or rare adverse event.

National, State, and Urban Area Vaccination Coverage Levels Among Children Aged 19-35 Months--United States, 2000

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.January-December 1998.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.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.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.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.

Variation in vaccination coverage among children of Hispanic ancestry

Background: Estimated vaccination coverage of Hispanic children is consistently lower than that of white non-Hispanic children. “Hispanic ethnicity” defines a highly heterogeneous group of the U.S. population; however, vaccination coverage by ancestry group has not been studied. This study explores differences in vaccination coverage among Hispanic children by ancestry group. Methods: The National Immunization Survey (NIS) uses a random-digit-dial sample of telephone numbers in each state and in 28 urban areas. The NIS provides vaccination coverage information representative of all U.S. children aged 19 to 35 months. We pooled NIS data from 1996 through 1999 and selected Hispanic and white non-Hispanic children for analysis. We categorized Hispanic children into the following ancestry groups: Mexican, Central American, Puerto Rican, Cuban, South American, and Dominican. We used t tests to detect differences in coverage between children of Hispanic ancestry, by group, compared to white non-Hispanic children, by vaccine, and the vaccination series 4:3:1:3. Results: Estimated vaccination coverage with 4:3:1:3 was 80.1% (95% CI, 79.6–80.6) among white non-Hispanic children. Estimated coverage was lower among Puerto Rican (75.8%; 95% CI, 72.1–79.5), Cuban (73.1%; 95% CI, 65.1–81.1), Mexican (71.7%; 95% CI, 69.9–73.5), and Central American (68.7%; 95% CI, 62.0–75.4) children, and was higher among South American (82.0%; 95% CI, 75.5–88.5) and Dominican (82.2%; 95% CI, 75.5–88.5) children; however, these differences were only statistically significant for Puerto Rican, Mexican, and Central American children. Among children living in poverty, estimated coverage with 4:3:1:3 was lower among Mexican (68.0%; 95% CI, 65.1–70.9), Central American (69.7%; 95% CI, 59.8–79.6), and South American (69.0%; 95% CI, 50.9–87.1) children than among white non-Hispanic children (73.4%; 95% CI, 71.6–75.2); however, this difference was significant only among Mexican children. Coverage was similar or somewhat higher among Puerto Rican (72.9%; 95% CI, 65.7–80.1) and Dominican (80.2%; 95% CI, 68.5–91.9) children than white non-Hispanic children living below poverty. Conclusions: Findings from the NIS strongly suggest that estimated vaccination coverage among children of Hispanic ancestry varies by group. Improved monitoring of vaccination coverage among Hispanics by community is necessary, and where undervaccination is identified, interventions should be matched to community needs.