A hidden vulnerable population: Young children up-to-date on vaccine series recommendations except influenza vaccines.

William K Bleser,Patricia Y Miranda,Daniel A Salmon,Maria Gańczak

doi:10.1371/journal.pone.0234466

William K Bleser, Patricia Y Miranda + Show 2 more

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https://doi.org/10.1371/journal.pone.0234466

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Abstract

Very young children (under 2 years old) have high risk for influenza-related complications. Children 6 months or older in the US are recommended to receive influenza vaccination annually, yet uptake is substantially lower than other routinely-recommended vaccines. Existing nationally-representative studies on very young child influenza vaccine uptake has several limitations: few examine provider-verified influenza vaccination (relying on parental report), few contain parental vaccine attitudes variables (known to be crucial to vaccine uptake), and none to our knowledge consider intersectionality of social disadvantage nor how influenza vaccine determinants differ from those of other recommended vaccines. This nationally-representative study examines provider-verified data on 7,246 children aged 6-23 months from the most recent (2011) National Immunization Survey to include the restricted Parental Concerns module, focusing on children up-to-date on a series of vaccines (the 4:3:1:3:3:1:4 series) but not influenza vaccines ("hidden vulnerability to influenza"). About 71% of children were up-to-date on the series yet only 33% on influenza vaccine recommendations by their second birthday; 44% had hidden vulnerability to influenza. Independent of parental history of vaccine refusal and a myriad of health services use factors, no parental history of delaying vaccination was associated with 7.5% (2.6-12.5) higher probability of hidden vulnerability to influenza despite being associated with 15.5% (10.8-20.2) lower probability of being up-to-date on neither the series nor influenza vaccines. Thus, parental compliance with broad child vaccine recommendations and lack of vaccine hesitancy may not indicate choice to vaccinate children against influenza. Examination of intersectionality suggests that maternal college education may not confer improved vaccination among non-Hispanic Black and Hispanic children despite that it does for non-Hispanic White children. Policymakers and researchers from public health, sociology, and other sectors need to collaborate to further examine how vaccine hesitancy and intersectional social disadvantage interact to affect influenza vaccine uptake in young US children.

Highlights

[38] The Parental Concerns (PC) module variables were merged with publicly-accessible National Immunization Survey (NIS) variables by National Center for Health Statistics (NCHS) analysts and accessed by the authors at the Penn State Federal Statistical Research Data Center, a Census Bureau facility housed at the Pennsylvania State University meeting all physical and information security requirements for federally-restricted data
A hidden vulnerable population: Young children up-to-date on vaccine series recommendations except influenza were UTD on both, 23% were UTD on neither, and 44% were UTD on the series but not influenza vaccines
A concerning main finding of this study is that nearly half of very young US children have “hidden vulnerability to influenza.”

Summary

Introduction

In the most recent published estimates (2017), the percent of children 19–35 months old up-todate (UTD) on other recommendations was: 83.2% for 4+ diphtheria-tetanus-acellular pertussis vaccine doses, 92.7% for 3+ poliovirus vaccine doses, 91.5% for 1+ measles-mumps-rubella vaccine doses, 80.7% for 3+ Haemophilus influenza type B vaccine doses, 91.4% for 3+ Hepatitis B vaccine doses, 91.0% for 1+ varicella vaccine doses, and 82.4% for 4+ pneumococcal conjugate vaccine doses. Research on determinants of uptake for influenza vaccination in the US, is limited, tending to focus on adult ( elderly) populations, and substantially less on children. There is no comparison of determinants of being UTD on influenza vaccines vs other vaccines This is an important research gap; that the 19-shot, 7-vaccine series (4:3:1:3:3:1:4) uptake rate is comparable to the recent 2018/2019 single-season peak in influenza vaccine uptake in young children indicates unique mechanisms affect parents’ decisions to vaccinate their child against influenza relative to every other routinely-recommended childhood vaccine

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