The 2006 NHIS survey approached 33,468 households in all 50 U.S. states, 4,264 (12.7%) of which were not surveyed because they either refused to participate (65.7%), were not home (24.7%), had language problems (1.5%), or indicated other reasons (8.1%). Among the 29,204 surveyed households, there were 29,868 families (<2% of households were multifamily), yielding data for 75,716 people; 20,903 respondents were children (≤17 years of age) and 54,813 respondents were adults (>17 years of age). Response rates were 90.7% and 82.3% for children and adults, respectively.
Among the surveyed families, 5,673 (19.0%) were excluded from analysis because of missing data (i.e., adult not sampled [98.6%] or lack of information on adult chronic disease status [1.4%]). Of the remaining 24,195 families, there were 8,976 high-risk adults, 1,697 (18.9%) of whom reported living with a family member ≤17 years of age (). Nearly 30% of adults aged 18–64 years with a chronic medical condition lived with a child, compared with only 3% of community-dwelling elderly people. Of the high-risk adults living with a child, 1,437 (86.9%) were aged 18–64 years and had a chronic medical condition, while 260 (13.2%) were ≥65 years of age.
2006 NHIS according to adult (>18 years of age) risk status for influenza complications and whether or not they live with children (≤17 years of age)
The overall influenza vaccination rate among children was 20.0%. It was highest among the toddler group (40.5%), followed by the preschool group (30.4%) and school-aged group (16.0%). School-aged children living with a high-risk adult family member reported higher influenza vaccination rates (20.0% vs. 15.0%, p<0.001) than counterparts not living with a high-risk adult (). We did not observe this difference among younger-aged children (<5 years of age), for whom influenza vaccination is universally recommended. Among families with children, influenza vaccination rates were 26.2% for adults aged 18–64 years with at least one chronic condition and 43.7% for people ≥65 years of age.
Child influenza vaccination coverage rates for 2005–2006 according to whether or not they live with an adult at high risk for influenza complications, 2006 National Health Interview Survey
Compared with unvaccinated children, those who received influenza vaccination were younger or more likely to have a chronic medical condition, health insurance, and frequent clinic visits (). The number of people living in the household was not significantly related to the odds of vaccination (data not shown). After adjusting for the child's age, gender, race, presence of a chronic medical condition, insurance coverage, and number of provider visits in the past year, those living with a high-risk adult were not significantly more likely to have received influenza vaccination (odds ratio = 1.16, 95% confidence interval 0.99, 1.36).
Table 2. Comparison of characteristics between vaccinated and unvaccinated children, and examination of characteristics associated with influenza vaccination among children using univariate and multivariate regression techniques, 2006 National Health Interview (more ...)
Among high-risk adult and child pairs, 61.3% belonged in group 4, in which neither received influenza vaccination (). Only 11.3% of sampled pairs reported influenza vaccine use in both adult and child. Receiving influenza vaccination was correlated with adults being older, being educated, having insurance coverage, having more chronic medical conditions, and exhibiting positive health behaviors, including abstinence from smoking and receipt of pneumococcal vaccination. Vaccine coverage in children was associated with younger age, presence of asthma or other chronic medical conditions, and more frequent health-care office visits. Of note, among families with an unvaccinated high-risk adult living with a vaccinated child, 20.7% of the adults reported no medical visits in the past year and 66.0% reported functional limitations. About 90.0% of unvaccinated children had at least one medical visit, and about 30.0% reported more than five visits in the previous year.
Comparison of sociodemographic and health characteristics of high-risk adult and childa living within a household, according to group classification based on influenza vaccination coverage, 2006 National Health Interview Survey