Vaccination Coverage Among Adults in the United States, National Health Interview Survey, 2015

Adults are at risk of illness, hospitalization, disability, and, in some cases, death from vaccine-preventable diseases, particularly influenza (flu) and pneumococcal disease. CDC recommends vaccinations for adults based on age, health conditions, prior vaccinations, and other factors (1) to prevent vaccine-preventable diseases and related outcomes. Many adults are not fully vaccinated, leaving them vulnerable to preventable illness.

This report summarizes data on vaccination coverage for U.S. adults 19 years and older from the 2015 National Health Interview Survey (NHIS) (2). The NHIS is an in-person survey of eligible civilian non-institutionalized adults. Flu vaccination coverage estimates for the 2015-16 season have been reported separately (3). Information on receipt of vaccinations, health and health care is self-reported and not verified through review of medical records or other means (4).

Key Findings

• Compared with 2014 NHIS estimates, modest increases in vaccination coverage occurred for some vaccines and age groups. Apart from these modest gains, vaccination coverage among adults in 2015 was similar to estimates from 2014.
  • Pneumococcal vaccination increased 2.8 percentage points to 23.0% among adults 19-64 years at increased risk for pneumococcal disease.
  • Tdap vaccination of adults 19 years and older increased by 3.1 percentage points overall to 23.1% and increased by 10.0 percentage points to 41.9% among adults living with an infant <1 year old.
  • Shingles (Herpes Zoster) vaccination increased 2.7 percentage points among adults 60 years and older to 30.6% and increased 3.2 percentage points among adults 65 years and older to 34.2%.
  • The 30% Healthy People 2020 target for shingles vaccination was met; however, this target is considerably lower than other targets (e.g., 70% for influenza vaccination of adults 19 years and older or 90% for pneumococcal vaccination of adults 65 years and older).
• Racial and ethnic vaccination differences persisted for all vaccinations in this report with generally lower coverage for most vaccinations among black and Hispanic adults compared with white adults.

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Conclusions/Recommendations

• While modest gains occurred in coverage for pneumococcal, Tdap, and herpes zoster vaccinations, coverage did not improve for other vaccinations and many adults remained unvaccinated with recommended vaccines.
  • Among adults 65 years and older:
    • Over one-third did not report pneumococcal or Td vaccination.
    • More than four out of every five did not report Tdap vaccination.
    • Nearly two-thirds did not report having had a shingles vaccination.
  • Among adults younger than 65 years with indications for pneumococcal vaccination, approximately 3 out of every 4 did not report ever having been vaccinated.
• The recommendation of a health care provider can ensure vaccination.
  • Following the Standards for Adult Immunization Practice, all providers should routinely assess adults’ vaccination status at every clinical encounter, strongly recommend needed vaccines, and either offer needed vaccines or refer their patients to another provider who can administer the recommended vaccine.
  • Vaccination providers should ensure reporting of vaccinations to their state’s immunization information system (IIS) to support consolidation of adult patients’ vaccination records (5, 6). Using their state’s IIS will help all providers access their patients’ immunization records and improve the ability to routinely and accurately assess their patients’ vaccination status.

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Who Was Vaccinated?

TABLE 1. Estimated proportion of adults ≥19 years who received pneumococcal vaccination, by age group, increased-risk status*, and race/ethnicity^†, National Health Interview Survey, United States, 2015

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TABLE 2. Estimated proportion of adults ≥19 years who received tetanus vaccination, not including and including pertussis vaccine, by age group, and race/ethnicity^†, National Health Interview Survey, United States, 2015

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TABLE 3. Estimated proportion of adults ≥19 years who received Hepatitis A vaccination, by age group, increased-risk status*, and race/ethnicity^†, National Health Interview Survey, United States, 2015

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TABLE 4. Estimated proportion of adults ≥19 years who received Hepatitis B vaccination, by age group, increased-risk status*, and race/ethnicity^†, National Health Interview Survey, United States, 2015

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TABLE 5. Estimated proportion of adults ≥60 years who received Herpes zoster vaccination, by age group and race/ethnicity^†, National Health Interview Survey, United States, 2015

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TABLE 6. Estimated proportion of adults 19-26 years who received HPV vaccination, by age group and race/ethnicity^†, National Health Interview Survey, United States, 2015

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What Can Be Done? (Recommendations)

Many adults in the United States have not received recommended vaccinations and racial and ethnic vaccination differences persist. Incorporating routine assessment of adult vaccination needs, recommendation, and offer of needed vaccinations into routine clinical care of adults can help improve vaccination rates and narrow racial and ethnic differences in vaccination coverage (4, 5, 6, 7).

To reduce missed opportunities for vaccination, providers and provider organizations are encouraged to increase awareness and use of tools for implementing the Standards for Adult Immunization Practice. In addition, CDC encourages healthcare providers to consider immunization quality improvement projects that implement measurable increases in adult immunization rates.

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Data Source and Methods

NHIS collects information about the health and health care of the noninstitutionalized U.S. civilian population using nationally representative samples. Face-to-face interviews are conducted by the U.S. Census Bureau for CDC’s National Center for Health Statistics. Non-institutionalized adults 19 years and older with interviews conducted during January–December 2015 were included in this analysis. The total adult sample was 33,348 persons aged ≥19 years. NHIS methods have been previously published. Questions about receipt of vaccinations recommended for adults are asked of one randomly selected adult within each family in the household and have been described previously (4). Weighted data were used to produce national vaccination coverage estimates. The weighted proportion of respondents who reported receiving selected vaccinations was calculated. Point estimates and 95% confidence intervals (CIs) were calculated by using statistical software to account for the complex sample design. T tests were used for comparisons between 2015 and 2014, and for comparisons of each level of each characteristic (e.g., race/ethnicity) to a chosen referent level (e.g., for race/ethnicity, non-Hispanic white was the reference group). Statistical significance was defined as p<0.05. Coverage estimates are not reported for small sample size (n<30) or relative standard error (standard error/estimates) >0.3.

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Limitations

• All data rely on self-report and were not validated with medical records. However, adult self-reported vaccination status has been shown to be ≥70% sensitive in one or more studies for pneumococcal, tetanus toxoid-containing, herpes zoster, and hepatitis B vaccines and ≥70% specific in one or more studies for all except tetanus and hepatitis B vaccination (8, 9, 10, 11).
• The response rate was 55.2%. Nonresponse bias can result if respondents and nonrespondents differ in their vaccination rates, and if survey weighting does not fully correct for this.
• The NHIS excluded persons in the military and those residing in institutions, which might result in underestimation or overestimation of vaccination coverage levels.
• The Tdap estimate is subject to considerable uncertainty. Respondents who reported a tetanus vaccination but were unable to say whether Td or Tdap was used during 2005–2015 were excluded from estimations of Tdap coverage, creating a potential for bias.
• NHIS survey data methods and limitations

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Authors: Walter W. Williams, MD, MPH¹, Peng-Jun Lu, MD, PhD ¹, Alissa O’Halloran, MSPH ^1,2, David K. Kim, MD ¹, Lisa A. Grohskopf, MD ³, Tamara Pilishvili, MPH ⁴, Tami H. Skoff ⁴, MS, Noele P. Nelson, MD, PhD ⁵, Rafael Harpaz, MD ⁶, Lauri E. Markowitz, MD ⁶ , Alfonso Rodriguez-Lainz, PhD, DVM ⁷, Amy Parker Fiebelkorn, MSN, MPH ¹, and Carolyn B. Bridges, MD ¹

¹Immunization Services Division, National Center for Immunization and Respiratory Diseases, CDC

²Leidos, Inc, Atlanta, GA

³Influenza Division, National Center for Immunization and Respiratory Diseases, CDC

⁴Division of Bacterial Diseases, National Center for Immunization and Respiratory Diseases, CDC

⁵Division of Viral Hepatitis, National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention, CDC

⁶Division of Viral Diseases, National Center for Immunization and Respiratory Diseases, CDC

₇Division of Global Migration and Quarantine, National Center for Emerging and Zoonotic Infectious Diseases, CDC

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References

1. CDC. Vaccine information for adults.
2. National Health Interview Survey public use data file.
3. CDC. FluVaxView 2015-16 Flu Season.
4. Williams WW, Lu P-J, O’Halloran AO, et al. Surveillance of vaccination coverage among adult populations – United States, 2014. MMWR Surveill Summ 2016;65(No. SS-1):1-36.
5. National Vaccine Advisory Committee. Recommendations from the National Vaccine Advisory Committee: standards for adult immunization practice. Public Health Rep 2014;129:115–23.
6. CDC. Standards for Adult Immunization Practice.
7. Community Preventive Services Task Force. The guide to community preventive services. Increasing appropriate vaccination: universally recommended vaccinations. Atlanta, GA: US Department of Health and Human Services, CDC; 2011.
8. Rolnick SJ, Parker ED, Nordin JD, Hedblom BD, Wei F, Kerby T, et al. Self-report compared to electronic medical record across eight adult vaccines: do results vary by demographic factors? Vaccine 2013;31(37):3928-3935.
9. Mangtani P, Shah A, Roberts JA. Validation of influenza and pneumococcal vaccine status in adults based on self-report. Epidemiol Infect 2007;135(1):139-143.
10. Donald RM, Baken L, Nelson A, Nichol KL. Validation of self-report of influenza and pneumococcal vaccination status in elderly outpatients. Am J Prev Med 1999;16:173-7.
11. Zimmerman RK, Raymund M, Janosky JE, et al. Sensitivity and specificity of patient self-report of influenza and pneumococcal polysaccharide vaccinations among elderly outpatients in diverse patient care strata. Vaccine 2003;21:1486-91.

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Footnotes

Abbreviations: CI = confidence interval; HPV = human papillomavirus; Td = tetanus-diphtheria toxoid; Tdap = tetanus, diphtheria, and acellular pertussis vaccine.

* Adults were considered at increased risk for pneumococcal disease if they had ever been told by a doctor or other health professional that they had diabetes, emphysema, chronic obstructive pulmonary disease, coronary heart disease, angina, heart attack, or other heart condition; had a diagnosis of cancer during the previous 12 months (excluding nonmelanoma skin cancer); had ever been told by a doctor or other health professional that they had lymphoma, leukemia, or blood cancer; had been told by a doctor or other health professional that they had chronic bronchitis or weak or failing kidneys during the preceding 12 months; had an asthma episode or attack during the preceding 12 months; or were current smokers. For hepatitis A and hepatitis B vaccination, data were collected on selected respondent characteristics that increase the risk for infection (travel to countries where hepatitis A infections are endemic and having chronic liver disease; having diabetes, travel to countries where hepatitis B infections are endemic, and having chronic liver disease, respectively).

^† Race/ethnicity was categorized as follows: Hispanic, black, white, Asian and “other.” In this report, persons identified as Hispanic might be of any race. Persons identified as black, white, Asian, or other race are non-Hispanic. “Other” includes American Indian/Alaska Native and persons who identified multiple races. The five racial/ethnic categories are mutually exclusive.

^§ Respondents were asked if they had ever had a pneumonia shot.

^¶ p<0.05 by t test for comparisons between 2015 and 2014 within each level of each characteristic.

^** p<0.05 by t test for comparisons with non-Hispanic white as the reference.

^†† Respondents were asked if they had received a tetanus shot in the past 10 years. Vaccinated respondents included adults who received Td during the past 10 years or Tdap during 2005–2015.

^§§ Respondents who had received a tetanus shot in the past 10 years were asked if their most recent shot was given in 2005 or later. Respondents who had received a tetanus shot since 2005 were asked if they were told that their most recent tetanus shot included the pertussis or whooping cough vaccine. Among 33,348 respondents aged ≥19 yrs, those without a “yes” or “no” classification for tetanus vaccination status within the preceding 10 years (n = 1,907 [5.7%]), for tetanus vaccination status during 2005–2015 (n = 591 [1.7%]), or those who reported tetanus vaccination during 2005–2015, but were not told vaccine type by the provider (n = 8,408 [25.2%]), did not know vaccine type (Td or Tdap) (n = 2,031 [6.1%]), or refused to answer or for whom data were not obtained (n=5 [0.01%]) were excluded, yielding a sample of 20,406 respondents aged ≥19 years for whom Tdap vaccination status could be assessed. In February 2012, ACIP recommended Tdap vaccination for all adults aged ≥19 years, including adults aged ≥65 years.

^¶¶ Estimate is not reliable due to small sample size (n<30) or relative standard error (standard error/estimates) >0.3.

*** Respondents were asked if they had ever received the hepatitis A vaccine, and if yes, were asked how many doses were received.

^††† Had traveled outside the United States to countries other than countries in Europe, Japan, Australia, New Zealand, or Canada since 1995.

^§§§ Had not traveled outside the United States to countries other than countries in Europe, Japan, Australia, New Zealand, or Canada since 1995.

^¶¶¶ p<0.05 by t test for comparisons between persons who had traveled outside the United States to countries other than countries in Europe, Japan, Australia, New Zealand, or Canada since 1995 and persons who had not traveled outside the United States to these areas since 1995.

^**** Respondents were asked if they had ever received the hepatitis B vaccine, and if yes, if they had received at least 3 doses or less than 3 doses.

^†††† Respondents were asked if they had ever received a shingles vaccine.

^§§§§ Respondents were asked if they had ever received the HPV shot or cervical cancer vaccine.

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