Pediatric vaccine adherence was improving before pandemic, but not for everyone

Key takeaways:

• From 2011 to 2020, adherence to the immunization schedule for children improved in the United States.
• However, rates differed by socioeconomic status.

WASHINGTON — Vaccine adherence was increasing among children in the United States in the years before the COVID-19 pandemic, but rates differed by socioeconomic status, researchers reported at the Pediatric Academic Societies Meeting.

The study assessed adherence to the combined seven-vaccine series, which includes shots against diphtheria, tetanus and acellular pertussis; polio; measles, mumps and rubella; hepatitis B virus; Haemophilus influenzae type b; varicella; and pneumonia.

“In the U.S., we do a really good job of tracking vaccination coverage in early childhood,” Sophia R. Newcomer, PhD, MPH, an associate professor at the University of Montana School of Public and Community Health Sciences, told Healio.

“That's typically measured by looking at kids when they turn 2 years old … to see which vaccines they've gotten and which vaccines they haven't gotten,” Newcomer said. “We were interested in looking a little deeper, and instead of just focusing on vaccination coverage, looking at how we can measure immunization schedule adherence.”

Newcomer and colleagues studied data from the CDC’s National Immunization Survey on immunization adherence between 2011 and 2020. Their analysis included 161,187 children.

“We looked at the ages when kids got vaccines relative to the age that they were recommended to receive that vaccine dose per that immunization schedule. And by doing that, we were able to then measure what percent of kids in the U.S. received their recommended vaccines on time,” Newcomer said.

In 2011, only 22.5% of U.S. children received all their recommended vaccines on time, but adherence increased to 34.9% in 2020.

“The rate of increase was not the same by socioeconomic status,” Newcomer said, calling it “concerning.”

The researchers found that children whose families had an income equal to or more than $75,000 experienced an average annual increase of 5.3% in on-time vaccinations, whereas children in lower income families saw only a 2.2% increase.

“We also saw similar trends with regard to [children on] private insurance vs. Medicaid,” Newcomer said.

She said she would “love to see” additional efforts focusing on timeliness of vaccination for children in low-income families.

“We have a strong federal program in place called the Vaccines for Children program that provides free vaccines to [uninsured] or underinsured children. However, even if cost isn't a barrier, there are other barriers to making sure that we get kids … vaccinated.”

“There have been significant improvements in early childhood vaccination timeliness in the decade prior to the COVID 19 pandemic,” Newcomer said. “However, disparities by socioeconomic indicators have been exacerbated, so efforts to improve the quality of vaccination services should prioritize addressing barriers to timely vaccination for low-income families.”