Vital Signs: Trends and Disparities in Childhood Vaccination Coverage by Vaccines for Children Program Eligibility — National Immunization Survey-Child, United States, 2012–2022

Introduction

Congress established the Vaccines for Children (VFC) program in 1994 to provide routine vaccines at no cost to eligible children. Since introduction of the VFC program, vaccination of children born during 1994–2023 will have prevented approximately 508 million illnesses and 1,129,000 deaths, saving nearly $2.7 trillion in societal costs (1). In 2023, VFC distributed approximately 74 million pediatric vaccine doses to participating health care provider locations (CDC, unpublished data, 2024). The VFC program is one of the nation’s primary health platforms created to promote health equity and improve the health of children.

VFC funds are allocated by the Centers for Medicare & Medicaid Services to CDC, and Medicaid providers can receive payment from Medicaid for vaccine administration services provided to Medicaid-eligible children.* CDC provides funding to 61 state, local, and territorial immunization programs to implement and oversee the VFC program (2). Persons aged ≤18 years who are Medicaid-eligible, uninsured, underinsured,^† or American Indian or Alaska Native (AI/AN)^§ are eligible to receive vaccines from VFC program providers at no cost. This report 1) describes characteristics of children eligible for the VFC program; 2) examines trends in routine vaccination coverage among VFC-eligible children; and 3) identifies gaps in vaccination coverage among VFC-eligible children compared with children who are not VFC-eligible.

Methods

Data Collection

NIS-Child is a nationally representative household survey that monitors coverage with Advisory Committee on Immunization Practices (ACIP)–recommended vaccines among children aged 19–35 months in the 50 states, the District of Columbia, and some U.S. territories^¶ using a random-digit–dial telephone sampling frame.** Parents and guardians (parents) of eligible children are interviewed to obtain child, maternal, and household information and to obtain consent to contact the child’s vaccine providers. With consent, parent-identified providers receive mailed immunization history questionnaires and are asked to provide information on vaccination types, doses, and dates administered and administrative data.

The overall household response rates^†† for 2012–2022 NIS-Child surveys ranged from 21.1% to 42.5%. Adequate provider data^§§ were available for 49.4% to 63.9% of children aged 19–35 months with a completed household interview, resulting in a sample size of 152,915 children.

Data Analysis

VFC-eligible children were defined as meeting one of these criteria: 1) AI/AN; 2) enrolled in Medicaid or the Indian Health Service (IHS) or uninsured^¶¶; or 3) ever received at least one vaccination at an IHS-operated center, Tribal health center, or urban Indian health care facility. Birth cohorts were constructed to assess coverage with ≥1 dose of MMR, 2–3 doses of rotavirus vaccine,*** the combined 7-vaccine series,^††† and other routinely recommended vaccines^§§§ among children born during 2011–2020. Kaplan-Meier techniques were used to estimate vaccination coverage with all vaccines by age 24 months, with a few exceptions.^¶¶¶ Percentage point differences in vaccination coverage between VFC-eligible and non–VFC-eligible children (i.e., coverage among VFC-eligible children minus coverage among non–VFC-eligible children) were analyzed using Z-tests to assess the gap in coverage by VFC program eligibility status. Weighted linear regression models assessed the average annual percentage point change (AAPPC) in vaccination coverage among children born during 2011–2020. Estimates of vaccination coverage with ≥1 dose MMR, rotavirus, and the combined 7-vaccine series were stratified by the child’s race and ethnicity, health insurance status, urbanicity,**** and household income. Analyses were conducted using SAS-callable SUDAAN (version 11.0.3, RTI International) with p<0.05 considered statistically significant. This activity was reviewed by CDC, deemed not research, and was conducted consistent with applicable federal law and CDC policy.^††††

Results

Characteristics of Children Eligible for the VFC Program

Among children aged 19–35 months who were born during 2011–2020, 52.2% were VFC eligible (Table 1). Among VFC-eligible children born in 2020, 93.4% were Medicaid-insured, 7.4% were AI/AN, 43.7% lived in households with income below the federal poverty level, and 48.1% lived in a metropolitan statistical area (MSA) principal city. The proportion of VFC-eligible children who were uninsured decreased from 8.1% of those born in 2011 to 3.1% of those born in 2020.

Overall Vaccination Coverage Among Children Eligible for the VFC Program

Among VFC-eligible children born during 2011–2020, coverage by age 24 months with ≥1 dose of MMR and the combined 7-vaccine series was stable (88.0%–89.9% and 61.4%–65.3%, respectively) (Figure) (Table 2). Rotavirus vaccination coverage by age 8 months was 64.8%–71.1%, increasing on average by 0.7 percentage points annually. Among VFC-eligible children born in 2020, coverage with ≥1 dose of MMR, rotavirus vaccine, and the combined 7-vaccine series was 89.6%, 71.0%, and 61.4%, respectively.

Among the vaccines included in the combined 7-vaccine series, coverage among VFC-eligible children born in 2020 was approximately 90% for first doses of vaccines (≥1 dose of varicella vaccine and ≥1 dose of MMR^§§§§) and for series administered earlier in life (≥3 doses of poliovirus vaccine and ≥3 doses of hepatitis B vaccine) (Supplementary Table, https://stacks.cdc.gov/view/cdc/159296). Coverage was 73.6%–76.7% with series requiring multiple doses by age 24 months, with some doses recommended after age 12 months (i.e., ≥4 doses of diphtheria, tetanus toxoids, and acellular pertussis vaccine; ≥4 doses pneumococcal conjugate vaccine; and the full series of Haemophilus influenzae type b conjugate vaccine).

Vaccination Coverage Among VFC-Eligible Children Born in 2020 by Selected Characteristics

Among VFC-eligible children born in 2020, coverage with ≥1 dose of MMR, rotavirus vaccine, and the combined 7-vaccine series among those who were uninsured was 18.9–34.7 percentage points lower than that among Medicaid-insured children (Table 3). Compared with coverage among children living at or above the poverty level, coverage with rotavirus vaccine and the combined 7-vaccine series among those living below the poverty level was 9.3–9.9 percentage points lower. By race and ethnicity, rotavirus vaccination coverage among AI/AN and Hispanic or Latino children was 6.9–8.9 percentage points higher than that among non-Hispanic White (White) children.

Comparison of Vaccination Coverage Among VFC-Eligible and Non–VFC-Eligible Children

Among all children born during 2011–2020, coverage with ≥1 dose of MMR, rotavirus vaccine, and the combined 7-vaccine series was lower among VFC-eligible children than among non–VFC-eligible children (Figure) (Table 2). During this period, the gap in coverage between VFC-eligible and non–VFC-eligible children increased for ≥1 dose of MMR (AAPPC = −0.2) and the combined 7-vaccine series (AAPPC = −0.6). Among children born in 2020, coverage with ≥1 dose of MMR, rotavirus vaccine, and the combined 7-vaccine series was 3.8, 11.5, and 13.8 percentage points, respectively, lower among VFC-eligible than among non–VFC-eligible children.

Among children born in 2020, all three vaccination coverage measures were lower among VFC-eligible children than among non–VFC-eligible children who were 1) White (−17.9 to −6.2 percentage points), 2) living at or above the poverty level (−11.2 to −4.6 percentage points), and 3) living in MSA principal cities (−12.8 to −3.3 percentage points) and MSA nonprincipal cities (−15.4 to −4.1 percentage points) (Table 3). Statistically significant gaps in coverage by sociodemographic characteristics were narrower for ≥1 dose of MMR (−6.2 to −3.3 percentage points) and wider for rotavirus vaccine (−17.9 to −7.7 percentage points) and the combined 7-vaccine series (−17.1 to −9.7 percentage points).

Discussion

More than one half of U.S. children (52.6%) born in 2020 were eligible for the VFC program, underscoring the vast scope of this program 30 years after it was enacted into law. Coverage among VFC-eligible children born during 2011–2020 with ≥1 dose of MMR remained high and stable, indicating that efforts to achieve and maintain measles elimination status in the United States have been supported through the VFC program. No differences in ≥1-dose MMR coverage among VFC-eligible children born in 2020 were found by race and ethnicity, poverty status, and urban-rural residency, demonstrating continued success in providing equitable access to vaccination through the VFC program (3). Increased coverage with rotavirus vaccine among VFC-eligible children born during 2011–2020 signals progress toward achieving high coverage with all routinely recommended immunizations.

Children born during 2018–2020 might have experienced health care disruptions resulting from the COVID-19 pandemic. However, previous analyses^¶¶¶¶ found no differences in overall vaccination coverage by age 24 months among children who were due for vaccination before the pandemic compared with those who were due for vaccination during the COVID-19 pandemic, including among children who were Medicaid-insured, uninsured, or AI/AN (4,5).

Coverage with the combined 7-vaccine series was 61.4% among VFC-eligible children born in 2020, highlighting room for improvement. By individual vaccine measures, coverage with first doses of vaccines and series administered earlier in life was high but was lower for multidose series vaccines, with additional doses administered at age >12 months. These patterns suggest potential barriers associated with receiving multidose series and for vaccinating VFC-eligible children during the second year of life. Provider reminder-recall systems and simultaneous administration of childhood vaccines at well-child visits have been established as effective strategies that can reduce missed vaccination opportunities and increase coverage (6,7).

Additional opportunities to improve coverage were identified among certain sociodemographic groups. Coverage was lower among uninsured children than among Medicaid-insured children, consistent with findings on vaccination coverage among uninsured adolescents and adults (8,9). Uninsured children are more likely to live in households with incomes below the poverty level, to have had no provider health care visits in the past year, and to be less likely to complete multidose vaccination series (8,10,11). The proportion of uninsured children was small and decreased from approximately 8.1% in 2011 to 3.1% in 2020. Efforts to further reduce the proportion of uninsured children, including increasing access to Medicaid, can facilitate connection to the health care system (12) and subsequently increase vaccination coverage (13).

Lower coverage with rotavirus vaccine and the combined 7-vaccine series was found among VFC-eligible children living below the poverty level compared with coverage among VFC-eligible children living at or above poverty. Although the VFC program provides vaccine at no cost, office visit fees or fees for nonvaccine services received during the visit (2) beyond vaccination cost might present potential barriers for low-income households, in addition to other barriers involving health care providers, parents, and the health care delivery system (14,15). Establishment of a place to receive ongoing routine care has been associated with increased likelihood of children in low-income households and VFC-eligible children being up to date with recommended vaccines (14,16).

Compared with coverage among non–VFC-eligible children, coverage overall was lower among VFC-eligible children, consistent with an earlier analysis of vaccination coverage among VFC-eligible children (17). High, yet lower ≥1-dose MMR coverage among VFC-eligible children compared with non–VFC-eligible children is concerning, because small pockets of low coverage have resulted in measles outbreaks (18,19). Despite improvements in rotavirus vaccination coverage among VFC-eligible children, coverage in this group was significantly lower than coverage among non–VFC-eligible children. Increased efforts are needed to ensure that parents of VFC-eligible children are aware of, have confidence in, and are able to obtain all recommended vaccines for their children.

Limitations

The findings in this report are subject to at least six limitations. First, overall household response rates for NIS-Child were low (range = 21.1%–42.5%), and 49.4%–63.9% of children with completed household interviews had provider-reported vaccination records. Selection bias resulting from low household response rates might have occurred if the characteristics of participants and nonparticipants differed systematically. Data were weighted to account for nonresponse and households without telephones, but some bias might remain, which could affect the generalizability of results. Second, total survey error assessments***** indicate that NIS-Child data might underestimate actual coverage with some vaccines; thus, actual vaccination coverage might be higher than reported. Third, the definition of VFC eligibility status used for this study might have resulted in underestimation of the actual VFC-eligible population because the operationalized definition includes Medicaid-enrolled but not Medicaid-eligible children. If Medicaid-eligible children differ from those who are Medicaid-enrolled, comparisons by VFC eligibility status could be higher or lower. Fourth, underinsured children who received vaccines at a federally qualified health center, a rural health center, or a deputized provider^{†††††} were excluded from the VFC-eligible group because of difficulty ascertaining information on the underinsured through NIS. This exclusion could result in potential misclassification of underinsured children as non–VFC-eligible. Fifth, health insurance status was determined at time of interview and might have varied during the child’s vaccination history, which could result in misclassification of VFC eligibility status. Sixth, this study was cross-sectional; therefore, underlying causes of observed differences in coverage over time or by VFC eligibility status could not be determined.

Implications for Public Health Practice

The VFC program has supported high and increasing childhood vaccination coverage for 30 years and is one of public health’s primary platforms for equity and ensuring that all children can access vaccines. Despite successes, the need to increase coverage with all routine vaccines and to reach children living in lower-income households and who lack insurance continues. Health care provider interventions to improve coverage include encouraging providers to make strong vaccine recommendations for their patients, strengthening family-provider relationships, providing parental education about vaccine benefits, using reminder-recall systems, reducing missed opportunities for vaccination, offering simultaneous administration of childhood vaccines, and administering catch-up vaccinations to all inadequately vaccinated children (6,7).

Enactment of the VFC program 30 years ago was a historic step in improving children’s lives and advancing public health. The data presented in this report demonstrate long-term program results for multiple birth cohorts of children. As new vaccines are added and immunization schedules become increasingly complex, maintenance and evolution of the VFC program could help sustain and further increase vaccination coverage. Realizing this will require efforts to promote participation in the VFC program by providers serving VFC-eligible children. CDC encourages providers to assess vaccination needs for all children at every health care visit and strongly recommend needed vaccines, and address patient barriers and promote confidence in vaccination.