Influenza Vaccination Coverage Among Health-Care Personnel --- United States, 2010--11 Influenza Season

The Advisory Committee on Immunization Practices (ACIP) and the Healthcare Infection Control Practices Advisory Committee recommend that all U.S. health-care personnel (HCP) be vaccinated annually against influenza (1). Nonetheless, influenza vaccination coverage among HCP in the United States has increased slowly over the past decade (2,3); during the 2009--10 influenza season, 61.9% of HCP received seasonal influenza vaccination (4). To update data with estimates from the 2010--11 influenza season, CDC conducted an Internet-based survey of 1,931 HCP who participated in three online survey panels. This report summarizes the results of that survey, which indicated that overall influenza vaccination coverage among HCP was 63.5% during the 2010--11 influenza season, similar to coverage for the 2009--10 season. Among HCP who reported working at a facility where vaccination was required by their employer, 98.1% were vaccinated. Among HCP without such an employer requirement but who were offered vaccination onsite, greater coverage was associated with a personal reminder from the employer to get vaccinated (69.9%), vaccination availability at no cost (67.9%), and vaccination availability for >1 day (68.8%). Influenza vaccination of HCP is needed to protect patients from HCP-transmitted disease. Maximizing influenza vaccination for all HCP is an important part of any comprehensive infection-control program.

To monitor 2010--11 influenza vaccination coverage among HCP, during April 1--27, 2011, CDC conducted a web-based survey of eligible HCP participating in three online survey panels. A total of 1,150 self-identified HCP were recruited from an online research panel operated by Knowledge Networks, Inc.*; an additional 534 persons were sampled from a specialized research panel composed primarily of physician specialists recruited through sources such as the American Medical Association master file, and 247 self-identified HCP were sampled from a marketing research panel composed of persons recruited through web advertising who agreed to participate in exchange for small amounts of financial compensation (i.e., $10 or less per survey). The total sample of 1,931 from all three sources was weighted to be nationally representative of demographic and geographic characteristics of the U.S. population of HCP as reflected in the most recent Current Population Survey.† Statistical significance of weighted differences was determined by Wald chi-square tests (p<0.05). Factors associated with increased vaccination coverage were assessed in a multivariable logistic regression model. The survey measured self-reported influenza vaccination from August 2010 through approximately mid-April 2011.

Among the HCP, 63.5% reported receiving a 2010--11 influenza vaccination (Table 1).§ Vaccination coverage was higher among HCP working in hospitals (71.1%), compared with those working in ambulatory or outpatient centers (61.5%), patient homes (53.6%), and "other" health-care settings (46.7%). Vaccination coverage among physicians and dentists (84.2%) was similar to coverage among nurse practitioners and physician assistants (82.6%) and was significantly higher than for those working in all other occupational groups (Table 1). Coverage also was significantly higher among persons aged ≥60 years (74.2%), compared with those aged 18--29 years (56.4%) and 30--44 years (57.8%). No significant differences in coverage were observed by race/ethnicity.

The prevalence of beliefs regarding influenza and influenza vaccination differed between vaccinated and unvaccinated HCP (Table 2). The greatest differences in prevalence were among HCP who believed getting vaccinated was worth the time and expense (vaccinated: 94.7%, unvaccinated: 45.8%), those who believed getting a vaccination would better protect persons around them (vaccinated: 89.1%, unvaccinated: 44.6%), those who believed vaccination could protect them from getting influenza (vaccinated: 92.7%, unvaccinated: 54.2%), and those who believed influenza to be a serious threat to their own health (vaccinated: 70.1%, unvaccinated: 34.2%). Among those vaccinated, 94.8% believed influenza vaccination was safe, compared with 66.2% of those not vaccinated who believed influenza vaccination was safe (Table 2).

Approximately 13% of HCP reported being required by their employers to be vaccinated for influenza. Among these persons, vaccination coverage was 98.1%, compared with 58.3% among those without an employer requirement (Table 1). Among HCP without an employer requirement who were offered vaccination onsite, greater coverage was associated with a personal reminder from the employer to get vaccinated (69.9% versus 59.5%), vaccination availability at no charge (67.9% versus 41.2%), and vaccination availability for >1 day (68.8% versus 41.4%) (Table 3). In all, 85.5% of HCP without an employer requirement were offered onsite vaccination at no charge on multiple days. Among HCP without onsite vaccination, neither a personal reminder from their employer to be vaccinated nor employers publicizing the risks and benefits of vaccination were associated with vaccination.

In a multivariable logistic regression model limited to HCP who did not have a vaccination requirement but were offered onsite vaccination, two incentives were associated with being vaccinated, after controlling for other incentives and demographic characteristics of HCP: a personal reminder to be vaccinated (odds ratio [OR] = 1.6; 95% confidence interval [CI] = 1.1--2.3) and vaccine availability at no cost and for >1 day (considered as a composite variable because of near complete overlap in the two occurrences) (OR = 2.8; CI = 1.7--4.5). Other incentives were not associated with being vaccinated in this model.

Reported by

Katherine M. Harris, PhD, Lori Uscher-Pines, PhD, RAND Corp., Arlington, Virginia. Carla L. Black, PhD, Gary L. Euler, DrPH, James A. Singleton, MS, Megan C. Lindley, MPH, Immunization Svcs Div, National Center for Immunization and Respiratory Diseases; Taranisia F. MacCannell, PhD, Div of Healthcare Quality Promotion, National Center for Preparedness, Detection, and Control of Infectious Diseases, CDC. Corresponding contributor: Carla L. Black, cblack2@cdc.gov, 404-639-8436.

Editorial Note

Vaccination of HCP against influenza has been shown to reduce illness and absenteeism and to reduce transmission of influenza to HCP, their families, and their patients (1). During the 2009--10 influenza season, influenza vaccination coverage among HCP reached peaks of 61.9% for the trivalent seasonal influenza vaccine and 64.3% for coverage with either the seasonal or pandemic monovalent 2009 H1N1 vaccine (4). Although increased attention to influenza resulting from the 2009 H1N1 pandemic was thought to have contributed to the increase in influenza vaccination coverage in 2009--10, comparable coverage was achieved during the 2010--11 season, with 63.5% of HCP in this analysis reporting receipt of influenza vaccination from August 2010 through mid-April 2011. However, to the extent that the coverage estimates derived from this survey are comparable to those from the National Health Interview Survey (NHIS), influenza vaccination coverage of HCP remains below the Healthy People 2020 target of 90% (as tracked by NHIS) (5).

The results of this survey indicate that 66.2% of unvaccinated HCP believed that the influenza vaccine was safe. However, when compared with those vaccinated, significantly lower percentages of unvaccinated HCP expressed the beliefs that getting vaccinated was worth the time and expense and that influenza vaccination can protect them and the persons around them from disease. These results indicate that programs to educate HCP regarding the seriousness of influenza and the effectiveness of the vaccine in protecting HCP and their patients from illness should continue.

Consistent with reports from health-care institutions that have required annual influenza vaccination as a condition for employment (6,7), vaccination coverage of 98.1% was reported among respondents who had an employer requirement for vaccination. Approximately 13% of surveyed HCP worked at facilities with such requirements, compared with 11% during the 2009--10 season (4). In the absence of requirements for vaccination, significantly higher vaccination coverage was achieved among employees who were offered vaccination onsite and free of charge for >1 day.

The findings in the report are subject to at least four limitations. First, the sample is not necessarily representative of all HCP in the United States, and estimates might not be directly comparable to those made for the 2009--10 season, because the sample used for that survey was restricted to members of the Knowledge Networks panel and not supplemented with members from the opt-in panels. Second, all results are based on self-report and are not substantiated by employment records or employer interviews. Third, the survey is possibly subject to selection bias, if participation in the survey is correlated with receipt of vaccination or certain beliefs. Finally, the definition of HCP used in this survey might vary slightly from definitions used in previously published surveys of vaccination coverage. Despite these limitations, Internet panel surveys are a useful surveillance tool for timely midseason and postseason evaluation of influenza vaccination coverage and knowledge, attitude, practice, and barrier data not provided by other sources of HCP data.

Since July 2007, the Joint Commission has required accredited critical access hospitals, other hospitals, and long-term care centers to establish an annual influenza vaccination program that would, at minimum, offer onsite influenza vaccination, monitor vaccination coverage, and provide education to staff members and licensed independent practitioners. Since 2009, CDC's National Healthcare Safety Network has provided a web-based tool for surveillance of vaccination of HCP in voluntarily enrolled health-care facilities.¶ Beginning in 2013, the Centers for Medicaid & Medicare Services might require hospitals to report HCP influenza vaccination coverage as part of its Hospital Inpatient Quality Reporting Program (8). Tracking vaccination coverage among HCP is needed as a measure of patient safety and to mark progress toward reaching the Healthy People 2020 target of 90%.

References

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5. US Department of Health and Human Services. Healthy people 2020. Increase the percentage of health-care personnel who are vaccinated annually against seasonal influenza. Objective IID-12.9. Washington, DC: US Department of Health and Human Services; 2011. Available at http://healthypeople.gov/2020/topicsobjectives2020/objectiveslist.aspx?topicid=23. Accessed August 15, 2011.
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8. Centers for Medicare & Medicaid Services. Medicare program. Hospital inpatient prospective payment systems for acute care hospitals and the long-term care hospital prospective payment system and fiscal year 2012 rates. Revisions to the reductions and increases to hospitals' FTE resident caps for graduate medical education payment purposes. Washington, DC: US Department of Health and Human Services, Centers for Medicare & Medicaid Services; 2011. Available at https://www.cms.gov/acuteinpatientpps/fr2012/itemdetail.asp?filtertype=none&filterbydid=-99&sortbydid=1&sortorder=ascending&itemid=cms1250103&intnumperpage=10. Accessed August 15, 2011.