Hepatitis B Vaccination Coverage Among Health-Care Personnel in the United States

Abstract

Objectives

We compared self-reported hepatitis B (HepB) vaccine coverage among health-care personnel (HCP) with HepB vaccine coverage among the general population and determined trends in vaccination coverage among HCP.

Methods

We used the 2010 National Health Interview Survey (NHIS) to determine the weighted proportion of self-reported ≥1- and ≥3-dose HepB vaccine coverage among HCP aged ≥18 years. We used logistic regression to determine independent predictors of vaccination and performed a trend analysis to determine changes in coverage from 2004 to 2010 using data from the 2004–2010 NHIS.

Results

Overall, 69.5% (95% confidence interval [CI] 67.2, 71.8) and 63.4% (95% CI 60.8, 65.9) of HCP reported receiving ≥1 and ≥3 doses of HepB vaccine, respectively, compared with 27.1% (95% CI 26.1, 28.1%) and 23.0% (95% CI 22.1, 24.0) among non-HCP. Among HCP with direct patient contact, 80.7% (95% CI 78.2, 83.1) and 74.0% (95% CI 71.2, 76.8) received ≥1 and ≥3 HepB vaccine doses, respectively. Independent predictors of vaccination included direct patient contact, having more than a high school education, influenza vaccination in the past year, and ever having been tested for HIV. There was no significant change in reported coverage from 2004 through 2010.

Conclusion

The 2010 HepB vaccine coverage estimate among HCP remained well below the Healthy People 2010 goal of 90%. Efforts to target unvaccinated HCP for preexposure HepB protection should be encouraged.

Working in health care has long been recognized as a risk for hepatitis B virus (HBV) exposure.^1–4 HBV is transmitted primarily through mucosal or cutaneous exposure to infectious blood or bodily fluids (e.g., sharps injury, non-intact skin, and burns).⁵ Studies from the 1980s and 1990s showed that up to 28% of health-care personnel (HCP) had serologic evidence of past or current HBV infection.^1–4 Exposures often go unrecognized, in part because HBV is stable in the environment for at least seven days and can be found in high titers on environmental surfaces even in the absence of visible blood.⁶ In previous investigations, most infected HCP could not recall an overt injury or caring for a patient who was known to be HBV infected.⁵

In 1982, a year after the first hepatitis B (HepB) vaccine in the United States was introduced, the Advisory Committee on Immunization Practices (ACIP) recommended a three-dose HepB vaccine series for HCP.⁷ In 1991, the Occupational Safety and Health Administration (OSHA) issued a Federal Standard that required employers to offer HepB vaccination at no cost to all occupationally exposed people.⁸ The ACIP recommendation, the OSHA Standard, introduction of Universal Precautions (now known as Standard Precautions), and the NeedleStick Safety and Prevention Act of 2001 likely contributed to the decreased HBV incidence among HCP during the past two decades; estimated numbers of incident cases among HCP decreased from 10,000 in 1982 to 304 in 2004.^7–12

Although the incidence of acute HBV infection has declined among HCP, the risks for exposure persist. For example, in 2005, the risk of needlestick injuries was estimated to be as high as 839 injuries per 1,000 HCP in the hospital setting.¹³ In addition, the National Surveillance System for Healthcare Workers estimated that from 1998 to 2007, 12% of source patients who were exposed to bodily fluids were positive for a bloodborne pathogen.¹⁴

Although the HepB vaccine has been recommended for HCP for more than two decades, vaccine coverage has remained below the Healthy People 2010 coverage goal of 90%.¹⁵ We used the National Health Interview Survey (NHIS) to estimate self-reported HepB vaccine coverage among HCP, determine independent predictors of vaccination, and track trends in vaccination coverage since 2004.

METHODS

We used the 2010 NHIS to estimate the weighted proportion of self-reported ≥1- and ≥3-dose HepB vaccine coverage among HCP and the general population aged ≥18 years. The NHIS is an annual cross-sectional household interview survey of the civilian noninstitutionalized U.S. population. The NHIS collects information on health behaviors, health indicators, and health-care use and access. Details on the NHIS design and sampling procedures have been previously described. In 2010, the final response rate for the core survey sample of adults was 60.8%.¹⁶

Self-reported vaccination coverage was estimated and stratified by the following sociodemographic and access-to-care variables: age group, sex, race/ethnicity, poverty level, education level, insurance status, number of physician visits in past year, and place of usual health care. Coverage was also stratified by whether a person had ever been tested for human immunodeficiency virus (HIV), had high-risk behavior for incident HBV infection, or had been vaccinated against seasonal influenza in the past year. In addition, because the ACIP recommends that HCP who have a reasonably anticipated risk for exposure to blood or other infectious body fluids should be vaccinated, we also stratified vaccination coverage by whether HCP had direct patient contact.⁹

For estimating vaccination coverage in 2010, we defined HCP status as a “yes” answer to the following question: “Do you currently volunteer or work in a hospital, medical clinic, doctor's office, dentist's office, nursing home, or some other health-care facility? This includes part-time and unpaid work in a health-care facility as well as professional nursing care provided in the home.” We considered HCP as having direct patient contact if they answered “yes” to the following question: “Do you provide direct patient care as part of your routine work? By direct patient care, we mean physical or hands-on contact with patients.” People were considered to be vaccinated with ≥1 dose of HepB vaccine if they responded “yes” to the following question: “Have you ever received the hepatitis B vaccine?” Those who answered “yes” were asked a follow-up question: “Did you receive at least 3 doses of the hepatitis B vaccine, or less than 3 doses?”

We considered people to be vaccinated against seasonal influenza if they answered “yes” to one of the following questions: “During the past 12 months, have you had a flu shot?” or “During the past 12 months, have you had a flu vaccine sprayed in your nose by a doctor or other health professional?” We defined individuals with high-risk behaviors as people who considered themselves at high risk for HIV infection, reported having a sexually transmitted disease other than HIV/acquired immunodeficiency syndrome (AIDS) during the previous five years, or reported any one of the following risk factors: men who have sex with men, injection of street drugs, having ever traded sex for money or drugs, being HIV-positive, having ever had sex with someone with any of the aforementioned risk factors, and having hemophilia with receipt of clotting factor concentrates. Hemophilia is not considered a risk behavior for HBV transmission; however, we were unable to exclude people with hemophilia because of the format of the survey question.

Subjects were divided into five-year age groups from 25 through 64 years of age. People aged ≥65 years were placed into one group. People aged 18–24 years were combined into one group because of the small numbers of HCP among this age group. All survey participants with “don't know,” “refused,” “not ascertained,” or missing responses to any of the aforementioned study variables (<9% of respondents) were excluded from the analysis.

We calculated point estimates and 95% confidence intervals (CIs) of ≥1- and ≥3-dose HepB vaccine coverage. All analyses were weighted to reflect the age, sex, and race/ethnicity of the U.S. noninstitutionalized civilian population. We used Wald Chi-square tests to assess the statistical significance of the association between vaccination coverage (≥1 and ≥3 doses) and sociodemographic, access-to-care, and other characteristics both by and within HCP status. Because certain sociodemographic and other characteristics have previously been found to be associated with vaccination rates, we conducted a multivariable logistic regression analysis to determine point estimates and 95% CIs of ≥1- and ≥3-dose HepB vaccine coverage among HCP adjusted for potential confounders, and to determine independent predictors of vaccination. We included all variables from the bivariate analysis in the multivariable regression model. We conducted a separate logistic regression model, which included HCP status as an independent variable, to determine if being an HCP was a predictor of vaccination and to determine the overall adjusted vaccination coverage among HCP; the variable for direct patient contact was excluded from this analysis due to collinearity with HCP status. For all statistical tests, we considered p<0.05 to be statistically significant, and we used Stata^® release 11 to calculate vaccination point estimates and to conduct the bivariate and multivariate analyses.¹⁷

In addition, we calculated point estimates and 95% CIs of ≥1-dose HepB vaccine coverage among HCP according to job description, using the standard occupation and industry categories recoded by the Centers for Disease Control and Prevention. The occupation and industry categories include physicians; nurses; others in health diagnosis and treating practitioners groups; clinical laboratorians; other health technologists; nursing, psychiatric, and home health aides; and other health-care support occupations.¹⁸ Because of the small sample size, we only conducted a descriptive analysis of job description.

We conducted a trend analysis for HepB vaccine coverage from 2004 through 2010 using a t-test for linear trends. Due to a change in the definition of HCP status within NHIS in 2009, we used a different definition for HCP for the trend analysis than what was used to calculate the vaccination point estimates and bivariate and multivariable analyses. We defined HCP for the trend analysis as individuals who were currently employed in a health-care occupation or in a health-care industry setting, based on the standard occupation and industry categories. We considered p<0.05 to be statistically significant. We used SUDAAN^® statistical software to conduct the test for linear trends.¹⁹

RESULTS

Demographic characteristics and access-to-care variables of the study sample, by HCP status, are shown in Table 1. A total of 24,497 adults aged ≥18 years were included in the sample, of whom 1,973 (8.1% weighted) were HCP. The median age of HCP was 44 years (range: 18–85 years). Approximately 75.3% of HCP were female and 68.8% were non-Hispanic white. The majority (79.8%) had more than a high school education, were insured (89.0%), and lived at or above the federal poverty level (FPL) (91.4%). About two-thirds (62.4%) of HCP had direct patient contact.

Table 1.

Sample characteristics of adults ≥18 years of age, by health-care personnel status: National Health Interview Survey, 2010

^aWald Chi-square p<0.05 for difference between health-care personnel and non-health-care personnel. Percentages were rounded to the nearest one-tenth.

^bIncludes American Indian/Alaska Native, Asian, and multiracial people

^cIncludes visits to non-physician health-care professionals

^dIncludes responses of “some other place,” hospital emergency room, and hospital outpatient departments

^eHigh-risk behaviors include people who considered themselves at high risk for HIV infection, people who reported having a sexually transmitted disease other than HIV/AIDS during the previous five years, and people who reported any one of the following risk factors: hemophilia with receipt of clotting factor concentrates, men who have sex with men, injecting street drugs, trading sex for money or drugs, testing positive for HIV, or having sex with someone with any of these risk factors.

NA = not applicable

FPL = federal poverty level

HMO = health maintenance organization

HIV = human immunodeficiency virus

AIDS = acquired immunodeficiency syndrome

HepB vaccination coverage and bivariate analysis

Vaccination coverage and results of the bivariate analysis for both HCP and non-HCP are shown in Table 2. Overall, 69.5% (95% CI 67.2, 71.8) and 63.4% (95% CI 60.8, 65.9) of HCP aged ≥18 years reported receiving ≥1 and ≥3 doses of HepB vaccine, respectively, compared with 27.1% (95% CI 26.1, 28.1) and 23.0% (95% CI 22.1, 24.0) of non-HCP (p<0.05 for both). Ninety-one percent of HCP who received ≥1 dose of HepB vaccine reported completing the vaccination series (data not shown). Among HCP who had direct patient contact, 80.7% (95% CI 78.2, 83.1) and 74.0% (95% CI 71.2, 76.9) reported receiving ≥1 and ≥3 doses of HepB vaccine, respectively (Table 2).

Table 2.

Hepatitis B vaccination rates by health-care personnel status: National Health Interview Survey, 2010

^aWald Chi-square test p<0.05 for comparison of health-care personnel and non-health-care personnel for each level of characteristic

^bWald Chi-square test p<0.05 for comparison for each level of characteristic within health-care personnel status to the designated referent

^cIncludes American Indian/Alaska Native, Asian, and multiracial people

^dIncludes visits to non-physician health-care providers

^eIncludes responses of “some other place,” hospital emergency room, and hospital outpatient departments

^fHigh-risk behaviors include people who considered themselves at high risk for HIV infection, people who reported having a sexually transmitted disease other than HIV/AIDS during the previous five years, and people who reported any one of the following risk factors: hemophilia with receipt of clotting factor concentrates, men who have sex with men, injecting street drugs, trading sex for money or drugs, testing positive for HIV, or having sex with someone with any of these risk factors.

CI = confidence interval

NA = not applicable

FPL = federal poverty level

HMO = health maintenance organization

HIV = human immunodeficiency virus

AIDS = acquired immunodeficiency syndrome

HCP aged 18–24 years reported higher ≥1-dose coverage (77.3%) than HCP aged 45–49 years (63.3%) and HCP aged ≥55 years (range: 36.9%–66.1%) (p<0.05) (Table 2). HCP who were female, had direct patient contact, had more than a high school education, had ≥10 health-care visits in the past year, were ever tested for HIV, and had high-risk behavior reported higher ≥1-dose coverage than HCP without these characteristics (all p<0.05). Similar characteristics were significantly associated with series completion (≥3 doses), except for respondents aged 45–49 and 55–59 years and those reporting high-risk behavior. Being at or above the FPL and being insured were associated with higher ≥3-dose coverage.

HepB vaccination coverage (≥1 dose) by health-care job description

The majority of each HCP profession reported receiving ≥1 HepB vaccine dose. Among physicians (n=93) and nurses (n=398), 88.8% (95% CI 80.8, 93.8) and 83.5% (95% CI 79.3, 86.9), respectively, reported receiving ≥1 HepB vaccine dose. Seventy-five percent (95% CI 50.7, 87.2) of clinical laboratory staff (n=32) and 76.5% (95% CI 70.3, 81.7) of other health technologists (n=231) reported receiving ≥1 HepB vaccine dose. Coverage for nursing, psychiatric, and home health aides (n=424) was 63.5% (95% CI 57.7, 68.9) and for other health-care support occupations (n=190) was 66.1% (95% CI 57.1, 74.1) (data not shown).

Multivariate and trend analysis among HCP

Results of the multivariate analysis for HCP are shown in Table 3. Decreased odds of reported receipt of ≥1 HepB vaccine dose were seen for HCP aged 60–64 years (adjusted odds ratio [AOR] = 0.37, p=0.047). Coverage of ≥1 vaccine dose did not differ significantly for most HCP aged ≤59 years. HCP with direct patient contact (AOR=3.14, p<0.001), those who had more than a high school education (AOR=2.43, p<0.001), those who were ever tested for HIV (AOR=1.61, p=0.020), and those who had received seasonal influenza vaccine in the past year (AOR=1.96, p=0.001) had greater odds of reported receipt of ≥1 HepB vaccine dose than HCP without the aforementioned characteristics. Characteristics of HCP who reported ≥3-dose coverage were similar except that age was no longer significantly associated with receiving ≥3 doses, and having high-risk behavior for incident HBV infection was associated with series completion. When HCP status was included as an independent variable within the logistic regression model, being an HCP was associated with both ≥1-dose (AOR=5.3, p<0.001) and ≥3-dose (AOR=4.95, p<0.001) vaccination (data not shown). There was no significant change in reported ≥1- or ≥3-dose vaccine coverage among HCP from 2004 to 2010 (test for trend, p>0.05) (Figure).

Table 3.

Multivariable logistic regression and adjusted hepatitis B vaccination rates among health-care personnel: National Health Interview Survey, 2010

^aIncludes American Indian/Alaska Native, Asian, and multiracial people

^bIncludes visits to non-physician health-care providers

^cIncludes responses of “some other place,” hospital emergency room, and hospital outpatient departments

^dHigh-risk behaviors include people who considered themselves at high risk for HIV infection, people who reported having a sexually transmitted disease other than HIV/AIDS during the previous five years, and people who reported any one of the following risk factors: hemophilia with receipt of clotting factor concentrates, men who have sex with men, injecting street drugs, trading sex for money or drugs, testing positive for HIV, or having sex with someone with any of these risk factors.

AOR = adjusted odds ratio

CI = confidence interval

Ref. = reference group

FPL = federal poverty level

HMO = health maintenance organization

HIV = human immunodeficiency virus

AIDS = acquired immunodeficiency syndrome

Figure.

Hepatitis B vaccination coverage among health-care personnel aged ≥18 years: National Health Interview Survey, 2004–2010

DISCUSSION

In 2010, overall self-reported HepB vaccination coverage among HCP aged ≥18 years was 69.5% and 63.4% for ≥1 and ≥3 doses, respectively. HCP with direct patient contact reported higher coverage (80.7% and 74.0% for ≥1 and ≥3 doses, respectively) than HCP without direct patient contact (51.1% and 45.8% for ≥1 and ≥3 doses, respectively), but coverage was still below the Healthy People 2010 goal of 90%. Independent predictors of vaccination included direct patient contact, having more than a high school education, influenza vaccination in the past year, and having ever been tested for HIV. There were no significant gains in coverage from 2004 through 2010.

Although reported HepB vaccination coverage among HCP was suboptimal, vaccination coverage was similar to vaccination coverage for influenza (64%) and tetanus (70%), two other vaccines recommended for HCP in the U.S.^20,21 Suboptimal HepB vaccine coverage in the past was, in part, due to concerns about vaccine side effects, lack of knowledge of the morbidity and mortality associated with HBV infection, and lack of knowledge of the risk of infection.^22–30 In a 2007 study of HepB vaccination among HCP, approximately one-third of unvaccinated HCP refused vaccination based on a belief that they could get HBV from vaccination.³¹ Although these barriers to vaccination suggest that additional education about the benefits and safety of vaccination might increase vaccination coverage among HCP, more recent evidence concerning influenza vaccination suggests that increased education does little to improve vaccination among HCP.^32–36

Having more than a high school education was associated with vaccination, a correlation that has been seen in other studies of adult vaccination.³⁷ Reported receipt of seasonal influenza vaccination in the past year among HCP was also associated with vaccination, which may indicate a more general acceptance of vaccination and preventive services.

One strategy to improve vaccination coverage among HCP is employer-mandated vaccination. Institutional requirements for influenza vaccination have led to higher vaccination levels. Miller et al. examined influenza vaccination coverage following institution of vaccination policies within a sample of U.S. hospitals and found that single-season influenza vaccination rates increased approximately 15% after instituting hospital policies requiring receipt or declination of influenza vaccination. Hospitals that instituted adverse consequences for refusal had higher coverage increases.³⁸ Policies requiring vaccination with tetanus, diphtheria, and acellular pertussis (Tdap) vaccine have also improved Tdap vaccination levels. In 2010, the University of North Carolina (UNC) made employment of HCP with direct patient contact conditional upon Tdap vaccination. UNC achieved a near-100% compliance rate after instituting the policy.³⁹ While we are unaware of any compulsory institutional policies for HepB vaccination of HCP, such requirements might be more difficult to implement than programs for influenza and Tdap because of the challenges related to documenting three doses of HepB vaccine that can be given during the course of several months or years. HepB vaccine is routinely administered to people of all ages in multiple settings, and documentation of vaccination might not be available, making it difficult to ascertain whether HCP are protected against HBV infection and if vaccination is indicated. However, documentation of HepB vaccination has increasingly been required of students entering health-care professional training programs; more than 90% of U.S. health professional schools require HepB vaccination for matriculation. This practice may account for higher coverage among HCP aged 18–29 years compared with non-HCP in this age group in our study.⁴⁰ Over time, documentation of HepB vaccination might be improved through availability of records from childhood, schools, or immunization registries.

Similar to age-related coverage rates among other groups at high risk for HBV infection, HepB vaccine coverage among HCP in our study was similar for younger HCP.³⁷ Coverage rates among younger HCP will increasingly be influenced by infant and adolescent HepB vaccination programs, which were implemented during 1991–1999.^41–43 Children who were vaccinated after the recommendations were implemented would have been 19–29 years of age in 2010, when the survey data were collected. Given the assumption that childhood vaccination programs and school matriculation requirements will enhance HepB vaccination coverage among younger HCP, it is reasonable to expect that coverage among HCP will increase in future years.

The 1991 OSHA requirement for employers to offer HepB vaccine at no cost to all workers who are occupationally exposed might also contribute to higher HepB vaccine coverage among HCP.⁸ Although this study clearly shows higher vaccination rates among HCP compared with non-HCP, the OSHA requirement might be expected to have had a greater impact on HCP vaccination rates. However, the OSHA requirement to offer HepB vaccine for free to employees does not ensure that employees will seek or accept vaccination; lack of seeking or accepting vaccination may contribute to the modest vaccination rate among HCP seen in this study.

Current ACIP recommendations state: “All unvaccinated people whose work- and training- related activities involve reasonably anticipated risk for exposure to blood or other infectious body fluids should be vaccinated with the complete, ≥3-dose HepB vaccine series.”⁹ HCP with direct patient contact had higher coverage than HCP without direct patient contact. While the majority of HCP with exposure to bodily fluids are involved in direct patient contact, a substantial percentage (28%) of exposures involved HCP without direct patient contact. During 1995–2007, 4% of reported exposures to bodily fluids were sustained by HCP whose jobs did not involve the routine handling of sharps, such as maintenance staff, housekeeping, and administrative personnel.¹⁵ Because of HBV stability and infectiousness, transmission can occur from exposure of non-intact skin (e.g., from blood spills, contaminated environmental surfaces, or non-patient care-related sharps injuries such as during waste handling), thereby also putting HCP without direct patient contact at risk of exposure.¹

HCP who had ever been tested for HIV were more likely to be vaccinated. We speculate that the association between ever having been tested for HIV and vaccination might be related to testing after occupational exposures, such as needlestick injuries. HCP who experienced needlestick injuries or other recognized exposures to body fluids might be more prone to seek or accept protection from bloodborne pathogens through vaccination.

Comprehensive strategies are needed to improve vaccination coverage for HCP. Recommended approaches include emphasizing the benefits of vaccination to staff and patients; using the level of vaccination coverage among HCP as a measure of patient safety and quality assurance; instituting electronic tracking of coverage levels by ward, unit, and occupation; targeting interventions to settings in which low vaccine coverage levels are identified; implementing catch-up vaccination programs for HCP who are already employed; and ensuring that newly hired HCP receive necessary vaccinations.^9,44–46 In addition, on descriptive analysis of the study data, home health aides and HCP within other health-care support occupations had the lowest reported HepB vaccination coverage. A strategy to improve overall coverage among HCP may also include targeting HCP by specific job description.

Limitations

This study was subject to several limitations. Vaccination status was self-reported and not verified by vaccination records. In two studies, agreement between self-report of adult vaccinations and provider records for influenza and pneumococcal vaccine was relatively high: 89%–92% for influenza and 79% for pneumococcal vaccine.^47–49 Studies assessing the validity of self-reported HepB vaccination through comparison with provider records are not available. One study, however, reported 70% agreement between self-report and serologic evidence of vaccination.⁴⁹ Recall bias could have led to over- or underestimation of coverage. Until adult vaccination records are more systematically collected and accessible in health-care settings, however, national surveys of self-reported vaccination status continue to be a viable method of monitoring vaccination coverage among HCP. Lastly, the NHIS is not specifically designed to survey HCP. However, NHIS uses a random, multistage sample designed to represent the civilian noninstitutionalized population of the U.S.; therefore, all noninstitutionalized populations (e.g., HCP and pregnant women) should be well represented.¹⁵

CONCLUSION

Despite the availability of a safe and effective vaccine that is available at no cost to most HCP, HepB vaccination coverage is below Healthy People 2010 objectives. Continued efforts are needed to increase HepB coverage among unvaccinated HCP to protect workers and patients.