Vaccination by Age 2: Coverage Holds Steady, but Gaps by Income and Race Persist

The Advisory Committee on Immunization Practices (ACIP) recommends vaccines against 15 potentially serious diseases by age 24 months. For nearly 30 years CDC's National Immunization Survey-Child (NIS-Child) has tracked how many U.S. children get them. This MMWR report adds the 2022 survey data and looks at children born in 2019–2020.

In short: coverage with most vaccines matched that of children born in 2017–2018. Differences by race and ethnicity, poverty, insurance and urban or rural residence persist, and for children in poverty some are widening.

Coverage by age 24 months

Only two changes were statistically significant: the hepatitis B birth dose rose 3.3 percentage points and at least one dose of hepatitis A rose 1.5 points. The share of completely unvaccinated children stayed at 1%. Coverage topped 90% for polio, hepatitis B, MMR and varicella; it was lowest for two doses of flu vaccine (61.3%) and the combined seven-vaccine series (69.1%).

Against the Healthy People 2030 targets, the 2019–2020 cohort met the goals for at least one dose of MMR (90.8% or more) and for no more than 1.3% of children receiving no vaccines, but not the goal of 90% for four doses of DTaP.

Who is left behind

• Insurance. Privately insured children had higher coverage than uninsured children and children on Medicaid or other insurance for every vaccine except the hepatitis B birth dose, where private and Medicaid did not differ. By age 24 months, 6.0% of uninsured children and 1.2% of children on Medicaid had received no vaccines, against 0.6% of privately insured children.
• Race and ethnicity. Black, Hispanic or Latino, and American Indian or Alaska Native (AI/AN) children all had lower coverage than White children with four doses of DTaP, four doses of pneumococcal vaccine, rotavirus, two doses of flu vaccine and the combined series. Coverage with the full Hib series was 12.1 points lower among AI/AN children than White children — especially worrying because Hib disease is far more common among AI/AN people.
• Poverty. Children below the federal poverty level had lower coverage than those at or above it for every vaccine except the hepatitis B birth dose.
• Rural areas. Children outside metropolitan areas had lower coverage than those in a metropolitan principal city for about half the vaccines tracked.
• Place. Coverage varied widely by jurisdiction, most of all for two doses of flu vaccine: from 33.0% in Mississippi to 85.9% in Connecticut.

Trends

Across birth cohorts from 2011 to 2020, coverage was stable for most vaccines, though two doses of flu vaccine fell 5.1 points for children born in 2020 compared with 2019. For the five latest cohorts (2016–2020), the hepatitis B birth dose rose 1.7 points a year, and one and two doses of hepatitis A rose 0.9 and 0.8 points a year; no vaccine declined.

Of 168 disparity trends checked for 2016–2020, six widened and one narrowed. The gap that most often grew was between children below the poverty level and those above it — for two doses of hepatitis A, two doses of flu vaccine and the combined series. Children in poverty may be losing ground.

What would help

The Vaccines for Children programme, which pays for recommended vaccines for eligible children, seemed to reduce racial and ethnic gaps, but more is needed. CDC is working with state Medicaid programmes, the Indian Health Service and the Association of Immunization Managers to spread the word about it.

Parents describe trouble scheduling appointments, gaps in knowing the vaccine schedule, scarce and costly child care for siblings, and lack of transport. Measures that have helped include:

• vaccinating outside doctors' offices — at health departments, child care centres and pharmacies;
• strong recommendations from providers;
• reminder and recall systems and standing orders;
• checking vaccination status at every visit;
• wider use of immunisation information systems for complete records, which can also pinpoint local areas and groups with low coverage.

How the survey works, and its limits

NIS-Child calls U.S. households with children aged 19–35 months, interviews the parent or guardian who knows the child's vaccinations best, and, with consent, asks the child's providers for records. Coverage comes from the providers' records. For 2022 the household response rate was 25.1%, and 49.7% of interviewed households had adequate provider data, giving 27,733 children.

Low response and incomplete provider data could bias the results, and weighting may not remove that. For 2022, total survey error was estimated to have underestimated coverage by 1.7 points for MMR, 3.3 for the hepatitis B birth dose and 9.2 for the combined series.

Sources

• Hill HA, Yankey D, Elam-Evans LD, Chen M, Singleton JA. "Vaccination Coverage by Age 24 Months Among Children Born in 2019 and 2020 — National Immunization Survey-Child, United States, 2020–2022." MMWR, CDC. https://www.cdc.gov/mmwr/volumes/72/wr/mm7244a3.htm
• Supplementary tables: coverage and trends, by jurisdiction, trends in disparities.
• Figures: CDC.
• Rewritten in hubnx's own words.