National Immunization Survey-Flu Research Articles

Population Attributable Fraction of Nonvaccination of Child and Adolescent Vaccines Attributed to Parental Vaccine Hesitancy, 2018-2019.

Understanding the role of vaccine hesitancy in undervaccination or nonvaccination of childhood vaccines is important for increasing vaccine confidence and uptake. We used data from April to June interviews in the 2018 and 2019 National Immunization Survey-Flu (n= 78,725, United States), a nationally representative cross-sectional household cellular telephone survey. We determined the adjusted population attributable fraction (PAF) for each recommended childhood vaccine to assess the contribution of vaccine hesitancy to the observed nonvaccination level. Hesitancy is defined as being somewhat or very hesitant toward childhood vaccines. Furthermore, we assessed the PAF of nonvaccination for influenza according to sociodemographic characteristics, Department of Health and Human Services region, and state. The proportion of nonvaccination attributed to parental vaccine hesitancy was lowest for hepatitis B birth dose vaccine (6.5%) and highest for ≥3-dose diphtheria and tetanus toxoids and acellular pertussis vaccine (31.3%). The PAF of influenza nonvaccination was highest for non-Hispanic Black populations (15.4%), households with high educational (17.7%) and income (16.5%) levels, and urban areas (16.1%). Among states, PAF ranged from 25.4% (New Hampshire) to 7.5% (Louisiana). Implementing strategies to increase vaccination confidence and uptake are important, particularly during the coronavirus disease 2019 pandemic.

Parental Vaccine Hesitancy and Childhood Influenza Vaccination.

To quantify the prevalence of parental vaccine hesitancy (VH) in the United States and examine the association of VH with sociodemographics and childhood influenza vaccination coverage. A 6-question VH module was included in the 2018 and 2019 National Immunization Survey-Flu, a telephone survey of households with children age 6 months to 17 years. The percentage of children having a parent reporting they were "hesitant about childhood shots" was 25.8% in 2018 and 19.5% in 2019. The prevalence of concern about the number of vaccines a child gets at one time impacting the decision to get their child vaccinated was 22.8% in 2018 and 19.1% in 2019; the prevalence of concern about serious, long-term side effects impacting the parent's decision to get their child vaccinated was 27.3% in 2018 and 21.7% in 2019. Only small differences in VH by sociodemographic variables were found, except for an 11.9 percentage point higher prevalence of "hesitant about childhood shots" and 9.9 percentage point higher prevalence of concerns about serious, long-term side effects among parents of Black compared with white children. In both seasons studied, children of parents reporting they were "hesitant about childhood shots" had 26 percentage points lower influenza vaccination coverage compared with children of parents not reporting hesitancy. One in 5 children in the United States have a parent who is vaccine hesitant, and hesitancy is negatively associated with childhood influenza vaccination. Monitoring VH could help inform immunization programs as they develop and target methods to increase vaccine confidence and vaccination coverage.

Rural, urban, and suburban differences in influenza vaccination coverage among children

Influenza vaccination is the primary way to prevent influenza, yet influenza vaccination coverage remains low in the United States. Previous studies have shown that children residing in rural areas have less access to healthcare and lower vaccination coverage for some vaccines. Influenza vaccination coverage among children 6 months–17 years by rural/urban residence during the 2011–12 through 2018–19 influenza seasons was examined using National Immunization Survey-Flu data. The Council of American Survey Research Organizations response rates for National Immunization Survey-Flu ranged from 48% to 65% (2011–12 through the 2017–18 seasons) for the landline sample and 20%–39% (2011–12 through the 2018–19 seasons) for the cellular telephone sample. Children residing in rural areas had influenza vaccination coverage that ranged from 7.9 (2012–13 season) to 12.6 (2016–17 season) percentage points lower than children residing in urban areas, and ranged from 4.5 (2012–13 season) to 7.4 (2016–17 season) percentage points lower than children residing in suburban areas. The differences in influenza vaccination coverage among rural, suburban, and urban children were consistent over the eight seasons studied. Lower influenza vaccination coverage was observed among rural children regardless of child’s age, mother’s education, household income, or number of children under 18 years of age in the household. Rural versus urban and suburban differences in influenza vaccination coverage remained statistically significant while adjusting for selected sociodemographic characteristics. A better understanding of the reasons for lower childhood influenza vaccination coverage for children in rural and suburban areas is needed.

Do parents prefer inactivated or live attenuated influenza vaccine for their children?

ObjectivesTo determine the proportion of children whose parents prefer them to receive live, attenuated influenza vaccine (LAIV) or inactivated influenza vaccine (IIV), examine reasons for preferences, and determine what percentage of vaccinated children receive other than the preferred type of vaccine and why. MethodsParental-reported data for the 2014–15 and 2015–16 influenza seasons from the National Immunization Survey-Flu (NIS-Flu), a random-digit-dialed, dual frame (landline and cellular telephone) survey of households with children, were analyzed. We calculated the proportions of vaccinated children aged 2–17 years whose parents preferred LAIV, IIV, or had no preference, and the proportions that were vaccinated with other than the preferred type of vaccine. ResultsFor the 2014–15 and 2015–16 seasons, 55.2% and 53.7%, respectively, of vaccinated children had parents who reported no preference for either IIV or LAIV. The percentage who preferred LAIV was 22.7% and 21.7%, and IIV was 22.1% and 24.7%. The most common reason given by parents for preferring LAIV was the child’s fear of needles (70.9%) and for preferring IIV was belief that the shot is more effective (29.0%). Approximately one-third of vaccinated children whose parents preferred LAIV received IIV only. ConclusionsThe main finding of this study was that most parents do not have a vaccine type preference for their children. The lack of overwhelming preference is advantageous for the maintenance of vaccination coverage levels during times when one vaccine type is not available or not recommended such as in the 2016–17 and 2017–18 seasons when there was a temporary recommendation not to administer LAIV.

Parental-Reported Full Influenza Vaccination Coverage of Children in the U.S.

Depending upon influenza vaccination history, children aged 6 months-8 years need one or two doses of influenza vaccine to be considered fully vaccinated. The objectives of this study were to quantify the percentage of children aged 6 months-8 years who were fully vaccinated against influenza based on parental report, overall, by state, and by sociodemographic characteristics, and to examine sociodemographic characteristics associated with being fully vaccinated. Data from the National Immunization Survey-Flu for the 2012-2013 and 2013-2014 influenza seasons were analyzed in 2015 using the Kaplan-Meier method to produce vaccination coverage estimates. Wald chi-square tests were used to test for bivariate associations, and Cox proportional hazards models were used to test for demographic characteristics independently associated with the child being fully vaccinated. The percentages of children aged 6 months-8 years who were fully vaccinated during the 2012-2013 and 2013-2014 influenza seasons were 41.0% and 45.2%, respectively. Full vaccination varied widely by state and was more likely for children requiring only one dose. Based on the statistical models, children likely to be fully vaccinated were older, non-black, had a mother with an education >12 years, or lived in a high-income household. Most children in the U.S. are not fully vaccinated against influenza. Reminder systems and interventions that reduce or remove barriers to children receiving their second doses of influenza vaccine may improve full influenza vaccination coverage among all children.

Place of influenza vaccination among children—United States, 2010–11 through 2013–14 influenza seasons

BackgroundStudies are published on settings adults receive influenza vaccination but few have reported on settings children are vaccinated and how this might be changing over time or vary by socio-demographics. MethodsData from the National Immunization Survey-Flu were analyzed to assess place of influenza vaccination among vaccinated children 6 months–17 years during the 2010–11, 2011–12, 2012–13, and 2013–14 influenza seasons. The percentage of children vaccinated at each place was calculated overall and by age, race/ethnicity, income, and Metropolitan Statistical Area (MSA). ResultsThe places children received influenza vaccination varied little over four recent influenza seasons. From the 2010–11 through 2013–14 influenza seasons the percentage of vaccinated children receiving influenza vaccination at a doctor's office was 64.1%, 65.1%, 65.3%, and 65.3%, respectively with no differences from one season to the next. Likewise, for vaccination at clinics or health centers (17.8%, 17.5%, 17.0%. 18.0%), health departments (3.2%, 3.6%, 3.0%, 2.8%), and other non-medical places (1.6%, 1.4%, 1.2%, 1.1%), there were no differences from one season to the next. There were some differences for vaccinations at hospitals, pharmacies, and schools. There was considerable variability in the place of influenza vaccination by age, race/ethnicity, income, and MSA. Fewer Hispanic children were vaccinated at a doctor's office than black, white, and other or multiple race children and fewer black children and children of other or multiple races were vaccinated at a doctor's office than white children. More children at or below the poverty level were vaccinated at a clinic or health center than all of the other income groups. ConclusionMost vaccinated children receive their influenza vaccination at a doctor's office. Place of vaccination changed little over four recent influenza seasons. Large variability in place of vaccination exists by age, race/ethnicity, income, and MSA. Monitoring place of vaccination can help shape future immunization programs.

Influenza vaccination coverage of Vaccine for Children (VFC)-entitled versus privately insured children, United States, 2011–2013

BackgroundThe Vaccines for Children (VFC) program provides vaccines at no cost to children who are Medicaid-eligible, uninsured, American Indian or Alaska Native (AI/AN), or underinsured and vaccinated at Federally Qualified Health Centers or Rural Health Clinics. The objective of this study was to compare influenza vaccination coverage of VFC-entitled to privately insured children in the United States, nationally, by state, and by selected socio-demographic variables. MethodsData from the National Immunization Survey-Flu (NIS-Flu) surveys were analyzed for the 2011–2012 and 2012–2013 influenza seasons for households with children 6 months–17 years. VFC-entitlement and private insurance status were defined based upon questions asked of the parent during the telephone interview. Influenza vaccination coverage estimates of children VFC-entitled versus privately insured were compared by t-tests, both nationally and within state, and within selected socio-demographic variables. ResultsFor both seasons studied, influenza coverage for VFC-entitled children did not significantly differ from coverage for privately insured children (2011–2012: 52.0%±1.9% versus 50.7%±1.2%; 2012–2013: 56.0%±1.6% versus 57.2%±1.2%). Among VFC-entitled children, uninsured children had lower coverage (2011–2012: 38.9%±4.7%; 2012–2013: 44.8%±3.5%) than Medicaid-eligible (2011–2012: 55.2%±2.1%; 2012–2013: 58.6%±1.9%) and AI/AN children (2011–2012: 54.4%±11.3%; 2012–2013: 54.6%±7.0%). Significant differences in vaccination coverage among VFC-entitled and privately insured children were observed within some subgroups of race/ethnicity, income, age, region, and living in a metropolitan statistical area principle city. ConclusionsAlthough finding few differences in influenza vaccination coverage among VFC-entitled versus privately insured children was encouraging, nearly half of all children were not vaccinated for influenza and coverage was particularly low among uninsured children. Additional public health interventions are needed to ensure that more children are vaccinated such as a strong recommendation from health care providers, utilization of immunization information systems, provider reminders, standing orders, and community-based interventions such as educational activities and expanded access to vaccination services.

Trends in childhood influenza vaccination coverage--U.S., 2004-2012.

We compared estimates of childhood influenza vaccination coverage by health status, age, and racial/ethnic group across eight consecutive influenza seasons (2004 through 2012) based on two survey systems to assess trends in childhood influenza vaccination coverage in the U.S. We used National Health Interview Survey (NHIS) and National Immunization Survey-Flu (NIS-Flu) data to estimate receipt of at least one dose of influenza vaccination among children aged 6 months to 17 years based on parental report. We computed estimates using Kaplan-Meier survival analysis methods. Based on the NHIS, overall influenza vaccination coverage with at least one dose of influenza vaccine among children increased from 16.2% during the 2004-2005 influenza season to 47.1% during the 2011-2012 influenza season. Children with health conditions that put them at high risk for complications from influenza had higher influenza vaccination coverage than children without these health conditions for all the seasons studied. In seven of the eight seasons studied, there were no significant differences in influenza vaccination coverage between non-Hispanic black and non-Hispanic white children. Influenza vaccination coverage estimates for children were slightly higher based on NIS-Flu data compared with NHIS data for the 2010-2011 and 2011-2012 influenza seasons (4.1 and 4.4 percentage points higher, respectively); both NIS-Flu and NHIS estimates had similar patterns of decreasing vaccination coverage with increasing age. Although influenza vaccination coverage among children continued to increase, by the 2011-2012 influenza season, only slightly less than half of U.S. children were vaccinated against influenza. Much improvement is needed to ensure all children aged ≥ 6 months are vaccinated annually against influenza.