2015-16 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). 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 2015-16 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,^‡ 2015-16 influenza season

		Total		Change from 2014-15|| to 2015-16 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	7,325	51.8	±2.0	-1.3	47.7	±2.5	52.6	±5.3	55.2	±4.5	62.8	±5.1
6-23 months	696	67.4	±6.7	1.0	65.5	±7.8	80.6	±17.2	62.4	±13.1	67.2	±17.6
2-4 years	1,214	61.8	±4.7	4.0	56.4	±6.5	73.1	±18.6	67.1	±10.6	65.0	±13.1
5-12 years	3,187	50.1	±2.5	-5.3	46.3	±3.5	45.6	±6.5	53.9	±5.9	65.2	±7.1
13-17 years	2,228	43.0	±3.5	1.2	39.7	±4.5	44.1	±10.0	46.4	±8.4	51.6	±10.4
NIS-Flu
Age group
6 months-17 years	126,846	59.3	±0.8	0.0	55.3	±0.9	60.9	±2.1	64.7	±2.0	64.8	±2.4
6-23 months	14,827	75.3	±1.7	0.7	74.1	±2.2	74.2	±4.9	75.6	±4.2	80.9	±4.3
2-4 years	23,886	66.8	±1.8	-1.0	63.2	±2.2	65.2	±5.6	72.3	±4.4	72.7	±4.8
5-12 years	54,825	61.8	±1.2	0.0	58.1	±1.3	63.3	±2.9	66.7	±3.0	65.8	±3.8
13-17 years	33,308	46.8	±1.4	0.2	42.9	±1.6	50.3	±4.1	52.6	±3.5	51.6	±4.1
Difference percent vaccinated, NIS-Flu – NHIS
Age group
6 months-17 years		7.5¶	±2.2		7.6¶	±2.7	8.3¶	±5.7	9.5¶	±4.9	2.0	±5.6
6-23 months		7.9¶	±6.9		8.6¶	±8.1	-6.4	±17.9	13.2	±13.8	13.7	±18.1
2-4 years		5.0	±5.0		6.8	±6.9	-7.9	±19.4	5.2	±11.5	7.7	±14.0
5-12 years		11.7¶	±2.8		11.8¶	±3.7	17.7¶	±7.1	12.8¶	±6.6	0.6	±8.1
13-17 years		3.8¶	±3.8		3.2	±4.8	6.2	±10.8	6.2	±9.1	0.0	±11.2

Abbreviation: CI = Confidence Interval

* Estimates of the percentage of people vaccinated are based on interviews conducted beginning September (NHIS) or October (NIS-Flu) 2015 through June 2016 and reported vaccinations from July 2015 through May 2016.

^† 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= 585 [11.5%] in NHIS, n= 13,767 [18.2%] in NIS-Flu).

^|| Estimates of the percentage of people vaccinated based on interviews conducted September (NHIS) or October (NIS-Flu) 2014 through June 2015 and reported vaccinations from July 2014 through May 2015.

^¶ Statistically significant difference between the 2015-16 NIS-Flu and the 2015-16 NHIS season by t-test (p<0.05).

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Table 2. 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,^§ 2015-16 influenza season

		Total		Change from 2014-15¶ to 2015-16 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	26,219	43.6	±1.2	-1.0	46.2	±1.2	40.5	±3.5	33.5	±3.1	46.5	±4.1
18-64 years	19,293	36.9	±1.2	-0.8	38.2	±1.4	36.1	±3.7	30.5	±3.3	42.2	±4.5
18-64 years with high-risk conditions	3,937	48.2	±2.5	2.2	47.9	±2.9	50.5	±7.6	47.2	±7.6	49.0	±10.6
18-64 years without high-risk conditions	15,319	34.2	±1.4	-1.6	35.7	±1.6	32.4	±4.1	27.4	±3.7	40.3	±4.5
18-49 years	12,497	32.3	±1.6	-0.3	33.0	±1.8	32.0	±4.5	28.0	±3.9	37.0	±4.7
18-49 years with high-risk conditions	1,729	37.1	±3.7	1.3	37.6	±4.3	40.1	±10.4	35.8	±11.8	33.8	±11.4
18-49 years without high-risk conditions	10,750	31.5	±1.6	-0.6	32.3	±2.0	30.9	±4.9	27.1	±4.1	37.1	±4.9
50-64 years	6,796	46.8	±2.0	-1.9	47.1	±2.2	45.5	±6.1	40.0	±6.1	55.7	±8.6
≥65 years	6,926	70.6	±1.8	-2.9	72.2	±2.0	65.2	±5.7	59.4	±8.0	73.6	±7.3
BRFSS
Age group
≥18 years	319,167	41.7	±0.4	-1.9	44.5	±0.6	36.6	±1.6	34.4	±1.8	41.0	±2.4
18-64 years	205,848	36.3	±0.6	-1.7	37.9	±0.6	33.3	±1.6	31.9	±2.0	39.0	±2.4
18-64 years with high-risk conditions	53,798	46.0	±1.2	-1.6	47.4	±1.2	42.3	±3.1	42.3	±4.3	48.2	±6.3
18-64 years without high-risk conditions	149,939	33.5	±0.6	-1.8	35.1	±0.6	29.9	±2.0	29.7	±2.2	36.0	±2.4
18-49 years	105,988	32.7	±0.8	-0.8	33.6	±0.8	30.4	±2.2	29.9	±2.2	37.1	±2.9
18-49 years with high-risk conditions	18,662	39.5	±2.0	0.2	40.0	±2.2	37.1	±4.9	37.6	±5.9	42.7	±9.4
18-49 years without high-risk conditions	86,111	31.5	±0.8	-1.1	32.5	±0.8	28.7	±2.4	28.8	±2.4	35.5	±2.7
50-64 years	99,860	43.6	±0.8	-3.4	44.8	±0.8	39.4	±2.5	40.7	±4.3	45.8	±3.9
≥65 years	113,319	63.4	±0.8	-3.3	64.6	±0.8	54.3	±3.1	62.9	±4.7	59.1	±5.7
Difference in percent vaccinated, BRFSS-NHIS
Age group
≥18 years		-1.9**	±1.3		-1.7**	±1.3	-3.9**	±3.8	0.9	±3.6	-5.5**	±4.8
18-64 years		-0.6	±1.3		-0.3	±1.5	-2.8	±4.0	1.4	±3.9	-3.2	±5.1
18-64 years with high-risk conditions		-2.2	±2.8		-0.5	±3.1	-8.2	±8.2	-4.9	±8.7	-0.8	±11.8
18-64 years without high-risk conditions		-0.7	±1.5		-0.6	±1.7	-2.5	±4.6	2.3	±4.3	-4.3	±5.1
18-49 years		0.4	±1.8		0.6	±2.0	-1.6	±5.0	1.9	±4.5	0.1	±5.5
18-49 years with high-risk conditions		2.4	±4.2		2.4	±4.8	-3.0	±11.1	1.8	±12.5	8.9	±14.8
18-49 years without high-risk conditions		0.0	±1.8		0.2	±2.2	-2.2	±5.5	1.7	±4.8	-1.6	±5.6
50-64 years		-3.2**	±2.2		-2.3	±2.3	-6.1	±6.6	0.7	±7.5	-9.9**	±9.4
≥65 years		-7.2**	±2.0		-7.6**	±2.2	-10.9**	±6.5	3.5	±9.3	-14.5**	±9.3

Abbreviation: CI = Confidence Interval

* Estimates of the percentage of people vaccinated are based on interviews conducted beginning September 2015 through June 2016 and reported vaccinations from July 2015 through May 2016.

^† 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). Because data on high risk status may be missing for some adults in both NHIS and BRFSS, the sample sizes for the high risk categories for the various age groups may not add up to the total sample size for that age group.

^‡ 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. population. Month of vaccination was imputed for respondents with missing month of vaccination data (n= 550 [3.8%] in NHIS, n= 9,995 [6.7%] in BRFSS).

^¶ Estimates of the percentage of people vaccinated based on interviews conducted September 2014 through June 2015 and reported vaccinations from July 2014 through May 2015.

** Statistically significant difference between the 2015-16 BRFSS and the 2015-16 NHIS season by t-test (p<0.05).