2013-14 NHIS, BRFSS, and NIS-Flu Influenza Data

The National Health Interview Survey (NHIS) is the data source used to monitor Healthy People 2020 objectives for influenza vaccination (IID-12.11-13)External. Influenza vaccination coverage estimates nationally and by state and selected local area from NIS-Flu and BRFSS are available each season approximately eleven months before final national estimates from NHIS. A comparison of national estimates from NIS-Flu and BRFSS to NHIS is available below for the 2013-14 season. Additional information on methods is available at Surveillance of Influenza Vaccination Coverage — United States, 2007–08 Through 2011–12 Influenza Seasons.

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Table 1. Influenza vaccination coverage* by age group and race/ethnicity, children 6 months through 17 years, National Health Interview Survey (NHIS) and National Immunization Survey-Flu (NIS-Flu), United States, 2013-14 influenza season

Total Change from 2012-13|| to 2013-14 influenza season
(percentage points)
White only,
non-Hispanic
Black only,
non-Hispanic
Hispanic Other,
non-Hispanic
Surveillance System Unweighted Sample Size %§ 95% CI % 95% CI % 95% CI§ % 95% CI % 95% CI
NHIS
   Age Group
      6 months-17 years 8,501 51.8 ±2.0 1.3 49.5 ±2.9 52.5 ±5.3 54.0 ±4.3 57.6 ±5.3
      6-23 months 811 63.5 ±5.7 -5.7 63.3 ±8.0 44.2 ±15.7 72.9 ±10.2 61.5 ±15.5
      2-4 years 1,521 57.5 ±3.7 -2.6 57.5 ±5.9 55.6 ±10.0 57.1 ±6.3 60.8 ±10.4
      5-12 years 3,997 52.0 ±2.9 2.8 48.1 ±4.7 55.6 ±7.6 55.4 ±5.7 58.5 ±8.0
      13-17 years 2,172 42.0 ±3.5 1.2 41.5 ±4.7 45.8 ±8.4 38.8 ±7.3 49.2 ±11.2
NIS-Flu
   Age Group
      6 months-17 years 126,860 58.9 ±0.8 2.3 55.2 ±0.9 57.2 ±2.2 66.0 ±2.1 64.9 ±2.1
      6-23 months 13,414 74.3 ±2.0 -2.6 74.6 ±2.1 67.9 ±6.8 76.6 ±4.7 75.3 ±5.3
      2-4 years 22,782 68.1 ±1.8 2.3 65.9 ±2.0 64.3 ±5.1 72.7 ±4.2 72.8 ±4.7
      5-12 years 62,590 61.0 ±1.1 2.4 56.5 ±1.1 59.3 ±2.9 69.7 ±3.0 66.1 ±2.7
      13-17 years 28,074 46.4 ±1.5 3.9 43.6 ±1.8 46.3 ±4.2 51.1 ±4.2 53.7 ±4.7
Difference Percent Vaccinated, NIS-Flu -NHIS
   Age Group
      6 months-17 years 7.1 ±2.2 5.7 ±3.0 4.7 ±5.7 12.0 ±4.8 7.3 ±5.7
      6-23 months 10.8 ±6.0 11.3 ±8.3 23.7 ±16.5 3.7 ±11.0 13.8 ±15.9
      2-4 years 10.6 ±4.1 8.4 ±6.2 8.7 ±11.2 15.6 ±7.6 12.0 ±11.0
      5-12 years 9.0 ±3.1 8.4 ±4.8 3.7 ±8.1 14.3 ±6.4 7.6 ±8.4
      13-17 years 4.4 ±3.8 2.1 ±5.0 0.5 ±9.4 12.3 ±8.4 4.5 ±12.0

Abbreviation: CI = Confidence Interval

* Estimates of the percentage of people vaccinated are based on interviews conducted beginning September (NHIS) or October (NIS-Flu) 2013 through June 2014 and reported vaccinations from July 2013 through May 2014.

Race/ethnicity is based on parental report. Persons categorized as white, black, or other were identified as non-Hispanic. Persons identified as Hispanic might be of any race. The other race category includes Asian, American Indian/Alaska Native (AI/AN), and multiple races.

Excludes U.S. territories.

§ Percentage vaccinated. Percentages are weighted to the non-institutionalized, U.S. civilian population. Month of vaccination was imputed for respondents with missing month of vaccination data (n= 710 [11.7.7%] in NHIS, n= 10,049 [7.7%] in NIS-Flu).

|| Estimates of the percentage of people vaccinated based on interviews conducted September (NHIS) or October (NIS-Flu) 2012 through June 2013 and reported vaccinations from August 2012 through May 2013.

Statistically significant difference between the 2013-14 NIS-Flu and the 2013-14 NHIS season by t-test (p<0.05).

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Table2. Influenza vaccination coverage* by age group, high-risk status, and race/ethnicity, adults 18 years and older, Behavioral Risk Factor Surveillance System (BRFSS) and National Health Interview Survey (NHIS) United States,§, 2013-14 influenza season

Total Change from 2012-13 to 2013-14 influenza season
(percentage points)
White only,
non-Hispanic
Black only,
non-Hispanic
Hispanic Other,
non-Hispanic
Surveillance System Unweighted Sample Size %|| 95% CI % 95% CI % 95% CI % 95% CI % 95% CI
NHIS
   Age Group
      ≥18 years 29,650 43.0 ±1.2 0.4 46.4 ±1.4 36.5 ±2.4 32.9 ±2.4 42.7 ±3.7
      18-64 years 22,914 36.5 ±1.2 0.4 38.8 ±1.6 32.8 ±2.5 29.6 ±2.4 38.5 ±3.9
      18-64 years with high-risk conditions 4,674 47.3 ±2.4 -2.2 48.9 ±2.9 42.9 ±5.5 40.8 ±5.7 53.8 ±9.2
      18-64 years without high-risk conditions 18,201 33.9 ±1.4 1.0 36.2 ±1.8 30.0 ±2.7 27.4 ±2.7 36.3 ±4.1
      18-49 years 15,262 31.4 ±1.4 0.9 32.6 ±2.0 30.0 ±3.1 26.8 ±2.9 34.8 ±4.1
      18-49 years with high-risk conditions 2,138 37.6 ±3.3 -1.4 38.4 ±4.3 36.0 ±8.0 31.6 ±7.4 47.9 ±14.1
      18-49 years without high-risk conditions 13,108 30.3 ±1.6 1.0 31.6 ±2.2 29.0 ±3.1 26.1 ±3.1 33.3 ±4.1
      50-64 years 7,652 47.7 ±2.0 -0.3 49.8 ±2.4 39.9 ±4.5 40.8 ±4.7 49.4 ±8.4
      ≥65 years 6,736 71.5 ±1.8 -0.1 73.4 ±2.2 60.5 ±6.3 64.0 ±5.7 70.3 ±7.1
BRFSS
   Age Group
      ≥18 years 354,572 42.2 ±0.4 0.7 45.4 ±0.4 35.6 ±1.4 33.1 ±1.4 40.1 ±2.0
      18-64 years 233,459 36.7 ±0.6 1.0 38.9 ±0.6 32.2 ±1.6 30.7 ±1.4 37.7 ±2.2
      18-64 years with high-risk conditions 60,603 46.3 ±1.0 0.9 48.5 ±1.2 40.2 ±3.1 41.5 ±3.1 48.4 ±5.7
      18-64 years without high-risk conditions 170,313 33.9 ±0.6 1.0 36.0 ±0.6 29.3 ±1.8 28.0 ±1.6 35.4 ±2.4
      18-49 years 119,708 32.3 ±0.6 1.2 33.9 ±0.8 29.3 ±2.0 28.0 ±1.8 35.7 ±2.5
      18-49 years with high-risk conditions 21,198 38.7 ±1.8 0.6 40.2 ±2.0 34.0 ±4.9 34.4 ±4.1 46.5 ±8.8
      18-49 years without high-risk conditions 97,005 31.1 ±0.8 1.3 32.6 ±0.8 28.2 ±2.2 26.8 ±1.8 34.2 ±2.5
      50-64 years 113,751 45.3 ±0.6 0.2 47.1 ±0.8 39.0 ±2.4 40.7 ±2.7 45.4 ±3.1
      ≥65 years 121,113 65.0 ±0.6 -1.2 66.6 ±0.6 56.6 ±2.7 57.8 ±3.1 62.4 ±3.7
Difference in percent vaccinated, BRFSS – NHIS
   Age Group
      ≥18 years -0.8 ±1.3 -1.0 ±1.5 -0.9 ±2.8 0.2 ±2.8 -2.6 ±4.2
      18-64 years 0.2 ±1.3 0.1 ±1.7 -0.6 ±3.0 1.1 ±2.8 -0.8 ±4.5
      18-64 years with high-risk conditions -1.0 ±2.6 -0.4 ±3.1 -2.7 ±6.3 0.7 ±6.5 -5.4 ±10.8
      18-64 years without high-risk conditions 0.0 ±1.5 -0.2 ±1.9 -0.7 ±3.2 0.6 ±3.1 -0.9 ±4.8
      18-49 years 0.9 ±1.5 1.3 ±2.2 -0.7 ±3.7 1.2 ±3.4 0.9 ±4.8
      18-49 years with high-risk conditions 1.1 ±3.8 1.8 ±4.7 -2.0 ±9.4 2.8 ±8.5 -1.4 ±16.6
      18-49 years without high-risk conditions 0.8 ±1.8 1.0 ±2.3 -0.8 ±3.8 0.7 ±3.6 0.9 ±4.8
      50-64 years -2.4** ±2.1 -2.7** ±2.5 -0.9 ±5.1 -0.1 ±5.4 -4.0 ±9.0
      ≥65 years -6.5** ±1.9 -6.8** ±2.3 -3.9 ±6.9 -6.2 ±6.5 -7.9 ±8.0

Abbreviation: CI = Confidence Interval

* Estimates of the percentage of people vaccinated are based on interviews conducted beginning September 2013 through June 2014 and reported vaccinations from July 2013 through May 2014.

High-risk definition based on the NHIS: adults categorized as at high risk for influenza-related complications self-reported one or more of the following: (1) ever being told by a physician they had diabetes, emphysema, chronic obstructive pulmonary disease, coronary heart disease, angina, heart attack, or other heart condition; (2) having a diagnosis of cancer during the preceding 12 months (excluding nonmelanoma skin cancer) or ever being told by a physician they have lymphoma, leukemia, or blood cancer during the previous 12 months; (3) being told by a physician they have chronic bronchitis or weak or failing kidneys; or (4) reporting an asthma episode or attack during the preceding 12 months. High-risk definition based on the BRFSS: adults categorized as at high risk for influenza-related complications self-reported diabetes, asthma, myocardial infarction, coronary heart disease, chronic obstructive pulmonary disease (COPD), or cancer (excluding skin cancer).

Race/ethnicity is based on self report. Persons categorized as white, black, or other were identified as non-Hispanic. Persons identified as Hispanic might be of any race. The other race category includes Asian, American Indian/Alaska Native (AI/AN), and multiple races.

§ Excludes U.S. territories.

|| Percentage vaccinated. Percentages are weighted to the non-institutionalized, U.S. civilian population. Month of vaccination was imputed for respondents with missing month of vaccination data (n= 503 [3.1%] in NHIS, n= 11,387 [6.8%] in BRFSS).

Estimates of the percentage of people vaccinated based on interviews conducted September 2012 through June 2013 and reported vaccinations from August 2012 through May 2013.

** Statistically significant difference between the 2013-14 BRFSS and the 2013-14 NHIS season by t-test (p<0.05).

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