Flu Vax for Toddlers Remained a Sticking Point Before Pandemic Hit

The CDC’s latest survey on routine childhood vaccination continued to show wide disparities for the influenza vaccine by insurance status, race, and geography, with only slight changes in overall vaccination rates from past years.

By age 24 months, over 90% of babies born in 2017 to 2018 received their recommended doses of four vaccines — poliovirus; hepatitis B; measles, mumps, and rubella (MMR); and varicella — according to findings in the 2018-2020 National Immunization Survey-Child (NIS-C).

However, only 60.6% of children that age were fully vaccinated for influenza, a small increase from the 56.6% recorded in the 2016-2018 survey, reported Holly Hill, MD, PhD, of the CDC, and colleagues in the Morbidity and Mortality Weekly Report.

The study was conducted with children who got vaccinated prior to COVID-19, so it does not account for the substantial decline in child vaccination rates during the pandemic, the authors said.

There were wide disparities in vaccination rates, particularly for influenza, the study group reported. Compared to 74.2% of privately insured children, only 36.4% of uninsured children were vaccinated for the flu. Influenza vaccination rates also varied greatly by geography — 80.2% of children under 2 years of age were vaccinated for the flu in Massachusetts, for example, whereas only 37.7% were in Alabama.

As in previous years, coverage was lower for Black and Hispanic children compared to white children for most vaccines, the researchers reported. Uninsured children were vaccinated at a lower clip for all vaccines.

“The presence of widespread and often substantial disparities in coverage with routinely recommended vaccines indicates a need for improvement to achieve equity in the national childhood vaccination program,” the authors wrote. Healthcare access, financial challenges, and vaccine hesitancy were and are potential barriers to vaccination, the researchers said.

“These [vaccine coverage] disparities were likely exacerbated during the current COVID-19 pandemic because of lockdown impacts of provider access and social and economic impacts on families and children,” Yvonne Maldonado, MD, chair of the American Academy of Pediatrics Committee on Infectious Diseases, said in an email to MedPage Today.

“Efforts to increase education and access to vaccines among these vulnerable populations must be improved at every level, including national, state, county, and local efforts to educate providers and families regarding the importance of vaccination, as well as making vaccination for children more accessible for families,” Maldonado said.

The NIS-C measures vaccination coverage for the diseases that the CDC Advisory Committee on Immunization Practices recommends children be vaccinated against before 24 months. Those vaccines include:

• Diphtheria, tetanus toxoids, and acellular pertussis (DTaP) (≥3 or ≥4 doses)
• Poliovirus (≥3 doses)
• MMR (≥1 dose)
• Haemophilus influenzae type B (primary or full series)
• Hepatitis B (dose within 3 days of birth and ≥3 doses)
• Varicella (≥1 dose)
• Pneumococcal (≥3 or ≥4 doses)
• Hepatitis A (≥1 dose and ≥2 doses by 35 months)
• Rotavirus (by age 8 months)
• Influenza (≥2 doses)

The survey also looks at coverage for the combined seven-vaccine series, which includes all of the above except hepatitis A, rotavirus, and influenza. Over 70% of children in the study received the full seven-vaccine series, but only 48.3% of uninsured children did, according to the researchers.

Only 1.0% of children received no vaccinations by 24 months of age, the study group reported. In uninsured children, that number was 3.3%, down from 7.4% in the 2016-2018 survey.

The present study included 29,114 children born in 2017 and 2018. NIS-C is conducted annually by random-digit-dialed mobile phone call. Interviewers reach out to families with children 19 to 35 months old to collect demographic data and request consent to contact their healthcare providers for vaccination records.

Response rates for the survey are historically low, with only 22.5% of households responding for this latest survey. Adequate vaccination data were obtained for 54.2% of the households that completed phone interviews. The authors point to the low response rates as a major limitation of the study: “This could introduce selection bias if study respondents and nonrespondents differed on factors relating to vaccination coverage,” they wrote.

Survey error was assessed for the last iteration of the NIS-C. In the 2019 study, coverage of the seven-vaccine series was underestimated by nine percentage points, which could be attributed to incomplete reporting by providers.

The researchers emphasized the importance of addressing low influenza vaccine coverage this year. “COVID-19 and influenza are likely to be co-circulating this fall and winter, which could put considerable strain on the public health and medical systems in the United States,” they said.