One in six toddlers did not complete childhood vaccination series before COVID-19
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Key takeaways:
- In 2019, only around 73% of toddlers completed their combined seven-vaccine series.
- Non-Hispanic Black children were more likely than non-Hispanic white children to not complete the series.
One in six toddlers in the United States did not complete the vaccination series for seven recommended childhood vaccines in 2019, the year before the COVID-19 pandemic, according to a study published in Pediatrics.
“Recent studies on low vaccination coverage have really focused on parental vaccine hesitancy, but less is known about of other causes of undervaccination,” Sarah Y. Michels, MPH, an epidemiology specialist at the Center for Population Health Research at the University of Montana, told Healio.
“Failing to complete a multidose series is likely due to other causes and logistical barriers to vaccination,” Michels said. “That was really what kind of prompted [our investigation].”
Michels and colleagues studied provider-verified vaccination data from the 2019 National Immunization Survey-Child on U.S. children aged 19 to 35 months and found three patterns of undervaccination for the combined seven-vaccine series, which protects toddlers from diphtheria, tetanus and acellular pertussis; pneumococcal infections; Haemophilus influenzae type b; hepatitis B virus; polio; measles, mumps and rubella (MMR); and varicella.
“First, we looked at the kids who completed all vaccinations in the combined seven-vaccine series, so that's one of our standard metrics for measuring vaccination coverage,” Michels said. “[Second was] not initiating the vaccine series — for example, if a family chose to skip their MMR vaccine or not receive their varicella vaccine. The third one, which was really our main focus for the study, was children who started all of their vaccine series who are missing their final doses from multidose series.”
Of the 16,365 toddlers included in the study, only 72.9% completed the combined seven-vaccine series, and 17.2% — approximately one in six —initiated but did not complete the one- or multidose vaccine series. Further, about 1.1% of children were completely unvaccinated for the combined seven-vaccine series, and approximately 9.9% had not initiated one or more of the seven vaccinations.
“Given what we know about fragmented care in the U.S health system and challenges sharing medical records, some of the findings weren't necessarily surprising,” Michels said. “But they did provide important information for kind of how to focus efforts moving forward.”
The researchers uncovered several characteristics among the children who initiated but did not complete the vaccine series, including that the family moved across state lines, there were two to three children in the household, or they lacked health insurance. Additionally, they found that non-Hispanic Black children had a greater risk of incomplete vaccination than non-Hispanic white children, whereas children living in low-income households and in rented homes were 25% to 30% more likely to fail to complete the multidose vaccine series.
“Our findings regarding socioeconomic and racial and ethnic disparities indicate that evidence-based strategies for making sure that children complete multidose series are not reaching all communities,” Michels said. “We know that vaccination coverage in early childhood kind of remains below national goals, but this study highlighted that our goals are within reach. One of our other main key points was that we found that if the children who are missing just one outstanding dose from the combined seven-vaccine series had received that final dose, the U.S. would have met some key national vaccination coverage goals.”
The authors said renewed efforts should be made to assist parents with vaccine reminders and other initiatives to address the economic barriers and racial disparities in early-childhood vaccine series completion rates.
“Given the disruptions due to the pandemic, extra effort is going to be needed to achieve and maintain high levels of vaccination coverage,” Michels said. “I think it's going to be really important to prioritize equity-focused intervention because we know that the risk of preventable infections is not equally distributed across the U.S.”