Vaccination by Age 2 for U.S. Children Born in 2015–2016: High, but Unequal

In brief

• The Advisory Committee on Immunization Practices (ACIP) recommends vaccinating children against 14 potentially serious illnesses before age 24 months.
• For children born in 2015 and 2016, coverage was high and stable for most vaccines, and only 1.3% had no vaccinations by their second birthday.
• Coverage was lower for children without private insurance, especially the uninsured.
• Better access to providers and insurance, giving every recommended vaccine at each visit, better education on vaccine safety and effectiveness, and local data to target communities at risk of measles outbreaks could raise it.

How it was measured

The National Immunization Survey–Child phones parents of children aged 19–35 months, then — with consent — asks their children's vaccination providers for records. CDC combined 2016–2018 surveys for 25,059 children born in 2015–2016 with adequate provider records, and for the first time reported by birth year rather than survey year. In 2018 the household response rate was 24.6%, and the survey switched to cellphones only.

Coverage by age 2

↑ statistically significant increase.

Coverage was at least 90% for polio, MMR, hepatitis B and varicella, and rose for the hepatitis B birth dose, hepatitis A and influenza — though influenza (56.6%) and the 7-vaccine series (68.5%) remained the lowest. From 2011 to 2016, coverage was stable by birth year, except hepatitis A (2 doses by 35 months), which rose from 71.1% to 76.6%; the share of children with no vaccinations crept up by about 0.09 percentage points a year.

Coverage with at least one dose of MMR vaccine by age 24 months, by state, children born in 2015–2016. CDC, MMWR.

MMR coverage was under 90% in 20 states; only six reached 94% or higher.

The insurance gap

Compared with privately insured children, the uninsured gap ranged from 7.8 percentage points (hepatitis B birth dose) to 33.8 (influenza). Gaps by race and ethnicity, poverty and urban or rural residence were also seen, but mostly smaller.

What it means

Measles shows the stakes: 22 outbreaks and 1,249 cases in the U.S. from January 1 to October 1, 2019, mostly among unvaccinated people. Pockets of low coverage — from poor access, or hesitancy fed by inaccurate information — make outbreaks more likely.

• Uninsured children can get free vaccines through the Vaccines for Children program, but promotion may not be reaching them.
• Longer office hours and transportation help could improve access whatever a child's insurance.
• Providers should use every visit to check and vaccinate. An analysis of children born 2005–2015 found the Medicaid–private gap in the fourth DTaP dose could have been cut by 42% had that dose not been missed at visits where other vaccines were given.
• Clear, accessible education and good conversations with providers can counter inaccurate claims, and local data — including better immunization information systems — can target communities at risk.

Limitations: estimates may be biased by an incomplete sample frame, low response and under-recorded vaccinations; and dropping landlines in 2018 means trends should be read with caution, though the effect is likely small. Reporting by birth year, at a fixed age of 24 months, may give slightly lower estimates than the old survey-year method.

Sources

Based on Holly A. Hill, James A. Singleton, David Yankey, Laurie D. Elam-Evans, S. Cassandra Pingali and Yoonjae Kang, "Vaccination Coverage by Age 24 Months Among Children Born in 2015 and 2016 — National Immunization Survey-Child, United States, 2016–2018," MMWR Morbidity and Mortality Weekly Report, volume 68, Centers for Disease Control and Prevention; a work of the United States government in the public domain.