In JAMA Network Open, a study today demonstrates that receipt of the recommended combined seven-vaccine series in US kids increased from 22.5% in 2011 to 35.6% in 2021. But improvements in on-time vaccination rates were lower for children from lower-income families and those without private health insurance, showing a link between vaccine coverage and household income.
The immunization schedule recommended in the United States says vaccinations, including diphtheria-tetanus-acellular pertussis (four doses), inactivated poliovirus (three doses), measles-mumps-rubella (one dose), hepatitis B (three doses), Haemophilus influenzae type b (three or four doses, depending on brand), varicella (one dose), and pneumococcal conjugate (four doses) should be provided at birth and ages 2, 4, 6, 12 to 15, and 15 to 18 months.
Increase in on-time vaccination highest among wealthier families
The study was based on vaccination timeliness for US children aged 0 to 19 months using data from the annual National Immunization Survey–Child (NIS-Child) conducted from 2011 through 2021. Included in the survey were 179,154 children, 31.4% of whom lived above the federal poverty level (more than $75,000 in annual family income), 32.4% lived at or above the poverty level ($75,000 or less), and 30.2% lived below the poverty level.
Children whose families had more than $75,000 in annual income had a 4.6% (95% confidence interval [CI], 4.0% to 5.2%) mean annual increase in on-time vaccination. The mean annual increase was 2.8% (95% CI, 2.0% to 3.6%) for children living at or above the poverty level, and 2.0% (95% CI, 1.0% to 3.0%) for children living below the poverty level.
The rate of improvement was greater for children from higher-income families and with private health insurance.
"The rate of improvement was greater for children from higher-income families and with private health insurance, compared with children from lower-income families or those with Medicaid insurance, respectively. As a result, disparities in vaccination timeliness by socioeconomic indicators widened over the 11-year period," the authors said.