Table of Contents

Component Description

The immunization (variable name prefix IMQ) section provides respondent-level data on immunizations, including the hepatitis A vaccine and the human papillomavirus (HPV) vaccine. The age of first HPV vaccination and number of HPV doses received is also obtained.

Eligible Sample

Participants aged 2 years and older were asked about the hepatitis A vaccination and participants 9 to 49 years of age were asked about the HPV vaccination.

Interview Setting and Mode of Administration

This questionnaire was asked, in the home or by telephone, by trained interviewers, using the Computer-Assisted Personal Interview (CAPI) system. A proxy provided information for survey participants who were under 16 years of age and for individuals who could not answer the questions themselves. The respondent selected the language of interview (English or Spanish) or requested that an interpreter be used.

The NHANES August 2021-August 2023 questionnaire is available on the NHANES website.

Quality Assurance & Quality Control

The CAPI system is programmed with built-in consistency checks to reduce data entry errors. CAPI also uses online help screens to assist interviewers in defining key terms used in the questionnaire. Interviewers were required to audio-record interviews. The recorded interviews were reviewed by interviewer supervisors and NCHS staff. 

Data Processing and Editing

Frequency counts were checked, and the reasonableness of question responses was reviewed. Edits were made to ensure the completeness, consistency, and analytic usefulness of the data. 

Analytic Notes

Several questions were dropped in NHANES 2021-2023 and are not included in this data file, including IMQ020, IMQ081A, IMQ081B, IMQ081C, and IMQ081D. 

The analysis of NHANES August 2021–August 2023 IMQ data must be conducted using the appropriate survey design variables, sample weights, and the basic demographic variables. Although these data were collected as part of the household questionnaire, if they are merged with the MEC exam data, exam sample weights should be used for the analyses. 

Please also refer to the NHANES Analytic Guidelines and the on-line NHANES Tutorial for details on the use of sample weights and other analytic issues.

Codebook and Frequencies

SEQN - Respondent sequence number

Variable Name:
SEQN
SAS Label:
Respondent sequence number
English Text:
Respondent sequence number.
Target:
Both males and females 2 YEARS - 150 YEARS

IMQ011 - Received Hepatitis A vaccine

Variable Name:
IMQ011
SAS Label:
Received Hepatitis A vaccine
English Text:
Hepatitis (Hep-a-ti-tis) A vaccine is given as a two dose series to some children older than 2 years and also to some adults, especially people who travel outside the United States. It has only been available since 1995. {Have you/Has SP} ever received hepatitis A vaccine?
English Instructions:
INTERVIEWER INSTRUCTION: A COMBINATION HEPATITIS A AND HEPATITIS B VACCINE SHOULD BE COUNTED AS THE A VACCINE FOR THE PURPOSE OF THIS QUESTION. CODE 'YES AT LEAST 2 DOSES' IF RESPONDENT ANSWERS 3 OR 4 DOSES WERE RECEIVED. CODE 'LESS THAN 2 DOSES' ONLY IF MENTIONED BY RESPONDENT.
Target:
Both males and females 2 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Yes, at least 2 doses 3465 3465
2 Less than 2 doses 547 4012
3 No doses 5460 9472
7 Refused 21 9493
9 Don't know 2072 11565
. Missing 0 11565

IMQ050 - CHECK ITEM

Variable Name:
IMQ050
English Instructions:
CHECK ITEM. IF SP = FEMALE AND AGE IS >= 9 AND <= 49, CONTINUE. IF SP = MALE AND AGE IS >= 9 AND <= 49, GO TO IMQ070. OTHERWISE, GO TO END OF SECTION.
Target:
Both males and females 2 YEARS - 150 YEARS

IMQ060 - Received HPV vaccine (Females)

Variable Name:
IMQ060
SAS Label:
Received HPV vaccine (Females)
English Text:
Human Papillomavirus (HPV) vaccine is given to prevent HPV infection, {cervical cancer,} and other conditions caused by HPV {in girls and women}. It is given in 2 or 3 separate doses. {Have you/Has SP} ever received one or more doses of the HPV vaccine? (The brand names for the HPV vaccines are Cervarix, Gardasil or Gardasil 9.)
Target:
Females only 9 YEARS - 49 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Yes 1095 1095 IMQ090
2 No 1512 2607 End of Section
7 Refused 2 2609 End of Section
9 Don't know 244 2853 End of Section
. Missing 8712 11565

IMQ070 - Received HPV vaccine (Males)

Variable Name:
IMQ070
SAS Label:
Received HPV vaccine (Males)
English Text:
Human Papillomavirus (HPV) vaccine is given to prevent HPV infection and conditions caused by HPV in boys and men. It is given in 2 or 3 separate doses. {Have you/Has SP} ever received one or more doses of the HPV vaccine? (The brand names for the vaccines are Gardasil or Gardasil 9.)
Target:
Males only 9 YEARS - 49 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Yes 637 637
2 No 1500 2137 End of Section
7 Refused 5 2142 End of Section
9 Don't know 351 2493 End of Section
. Missing 9072 11565

IMQ090 - Age first dose HPV

Variable Name:
IMQ090
SAS Label:
Age first dose HPV
English Text:
How old {were you/was SP} when {you/SP} received {your/his/her/SP's} first dose of HPV vaccine?
Target:
Both males and females 9 YEARS - 49 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 to 46 Range of Values 1331 1331
777 Refused 2 1333
999 Don't know 399 1732
. Missing 9833 11565

IMQ100 - Received HPV, # of doses

Variable Name:
IMQ100
SAS Label:
Received HPV, # of doses
English Text:
How many doses of the vaccine {have you/has SP} received?
Target:
Both males and females 9 YEARS - 49 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 1 Dose 387 387
2 2 Doses 720 1107
3 3 Doses 418 1525
7 Refused 1 1526
9 Don't know 206 1732
. Missing 9833 11565