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Interventions to Increase Influenza Vaccination of Health-Care Workers --- California and Minnesota

Vaccination of health-care workers (HCWs) has been shown to reduce influenza infection and absenteeism among HCWs (1), prevent mortality in their patients (2), and result in financial savings to sponsoring health institutions (3). However, influenza vaccination coverage among HCWs in the United States remains low (4--6); in 2003, coverage among HCWs was 40.1% (CDC, unpublished data, 2005). This report describes strategies implemented in three clinical settings that increased the proportion of HCWs who received influenza vaccination. The results demonstrate the value of making influenza vaccination convenient and available at no cost to HCWs.

Educational Campaigns and Vaccine Days in Nursing Homes

In spring 2002, the California Department of Health Services, in collaboration with local health departments, conducted a knowledge, attitudes, and behaviors study of HCWs in 30 southern California nursing homes. This study determined that problems with vaccine access and misconceptions regarding influenza and the vaccine were associated with nonvaccination. The study results were used to develop two interventions: 1) educational campaigns that emphasized the seriousness of influenza and addressed employee misconceptions about influenza and the vaccine (through employee in-services, fact sheets distributed with employee paychecks, and informational handouts and posters); and 2) Vaccine Days offering influenza vaccination free of charge to all HCWs on designated days at the nursing home.

To evaluate the effectiveness of these interventions, the California Department of Health Services conducted a controlled study in 70 southern California nursing homes during the 2002--03 influenza season. Nursing homes were selected by convenience sample and represented approximately 14% of nursing homes in the areas from where they were selected. They were assigned to one of four groups: 1) group A (n = 25), which conducted no interventions; 2) group B (n = 15), which conducted an educational campaign; 3) group C (n = 15), which held Vaccine Days; and 4) group D (n = 15), which conducted both an educational campaign and held Vaccine Days.

Sixty-seven (95%) nursing homes completed the study, and 4,338 (61%) of the 7,123 HCWs returned postintervention vaccination questionnaires; response rates did not vary by study group but did range from 56% to 68% by nursing home. According to preliminary analysis, when compared with the 27% vaccination coverage in the control group (group A), Vaccine Days were effective in increasing coverage when implemented in combination with the educational campaign (group D) (53% coverage; adjusted odds ratio [AOR] = 3.54; 95% confidence interval [CI] = 2.17--5.72) and when implemented alone (group C) (45%; AOR = 2.28; CI = 1.30--3.98). However, an educational campaign alone (group B) did not significantly increase HCW vaccine coverage (34%; AOR = 1.31; CI = 0.76--2.25).

Mobile Vaccination Cart at a Veterans Affairs Medical Center

During the early 1980s, influenza vaccination rates among employees of the Minneapolis (Minnesota) Veterans Affairs Medical Center (VAMC) were less than 25%. In 1985, as part of a comprehensive effort to increase vaccination coverage among HCWs, VAMC initiated a Mobile Vaccination Cart Program. The program maximized both convenience and efficiency through advertising to employees, prescheduled vaccination times for employees in all wards and departments, streamlined documentation of vaccination, provision of free vaccination, and standing orders that authorized nurses to vaccinate VAMC employees.

The program is reviewed and endorsed each year by the VAMC Infection Control Committee. One employee-health nurse and two infection-control nurses set aside 2 weeks in mid-October to operate the mobile carts, which are stocked with vaccine in syringes, vaccine information statements, sharps disposal containers, alcohol hand rub, alcohol wipes, adhesive bandages, documentation forms, and injectable epinephrine with orders for administration in the event of an acute hypersensitivity reaction. Employees receive and are encouraged to read information about vaccination before the cart comes to their area. Inpatient wards are visited at the change of shift. Appointments are also made for other clinical areas (e.g., laboratory and radiology) and for departments with employees that might have direct patient contact (e.g., supply or housekeeping). These schedules are posted, and employees are encouraged to "go to the cart" if another time and location is more convenient than the scheduled time for their work area. In addition, employees can also be vaccinated at walk-in clinics for patients. A standardized, preprinted documentation form further streamlines record-keeping.

Since the program was introduced in 1985, influenza vaccination rates of VAMC HCWs increased steadily to 46% (1,475 of 3,177 employees) for the 1996--97 season and to 65% (1,950 of 3,008) for the 2003--04 season. The Mobile Vaccination Cart Program enables nurses to answer questions and educate employees about other strategies for preventing influenza transmission, such as proper hand hygiene. VAMC attributed the steady increase in coverage to the cumulative impact of ongoing education, communication, and access.

Vaccination Clinics, Peer Vaccination, and Incentives at Mayo Clinic

Yearly influenza vaccination of the approximately 25,000 employees at Mayo Clinic in Rochester, Minnesota, is a challenge. During the 1999--2000 influenza season, 53.6% of Mayo staff members received influenza vaccination. Since 2000, despite national vaccine shortages and delays, Mayo Clinic has conducted intensive influenza vaccination efforts among its employees by making vaccination increasingly convenient and by using gift incentives and peer advocacy.

During the 2000--01 influenza season, Mayo Clinic offered free vaccine to employees at large vaccination clinics in employee cafeterias and the employee health service center. Immediately after these clinics, a Peer Vaccination Program (PVP) enabling nurses to vaccinate coworkers at their worksites was offered to all inpatient units. The PVP eliminated the expense and logistical difficulty of establishing and staffing additional vaccination clinics and made vaccination more convenient for HCWs. Under this combination of programs, 42.2% of all Mayo employees were vaccinated during the 2000--01 season, despite barriers caused by vaccination shortage and delays. During the 2001--02 season, continued shortages and delays prevented many employees from receiving vaccination. As vaccine became available, employees in high-risk categories were vaccinated first, mini-clinics were offered throughout the Mayo campus at convenient locations, and 42.6% of all employees were ultimately vaccinated.

During the 2002--03 influenza season, an incentive program was added to the influenza clinics. Employees vaccinated at one of the main clinics could sign up for incentive gifts, such as movie tickets or health books, which were distributed through a drawing after the influenza clinics were held. In addition, electronic posters advertising the clinics were placed at all staff entrances, cafeterias, and elevator banks. Vaccination coverage for that season increased to 56.4%.

During the 2003--04 influenza season, Mayo Clinic placed additional emphasis on education and vaccine accessibility, resulting in vaccination of 76.5% of the 26,261 employees. As in previous years, vaccine was administered free of charge at influenza clinics held in employee cafeterias and offered through the PVP, and gift incentives were again provided. In December 2003, Mayo Clinic began offering vaccination at departmental grand rounds, further eliminating access and inconvenience barriers. Staff members were educated about the risk for influenza, the need for vaccination, and the safety and efficacy of the vaccine through newsletters, flyers, and poster presentations throughout the vaccination season. Furthermore, influenza vaccine "champions" (i.e., employee-health and infection-control staff members) promoted the importance of influenza vaccination by conducting grand rounds, sending notices to all employees by e-mail, attending meetings with nursing supervisors, staffing a telephone hotline, and answering questions at the vaccination clinics.

Reported by: AC Kimura, MD, JI Higa, MPH, C Nguyen, MPH, California Dept of Health Svcs, Gardena; DJ Vugia, MD, California Dept of Health Svcs, Berkeley. M Dysart, L Ellingson, L Chelstrom, MPH, J Thurn, MD, KL Nichol, MD, Minneapolis Veterans Admin Medical Center; GA Poland, MD, J Dean, Mayo Clinic College of Medicine, Rochester, Minnesota. KA Lees, MPH, DB Fishbein, MD, National Immunization Program, CDC.

Editorial Note:

Influenza vaccination among U.S. HCWs increased from 10% in 1989 to 34% in 1997 (4) and only slowly increased to 40% in 2003. The interventions described in this report underscore the importance of making vaccination convenient and available at no cost to HCWs. The study of southern California nursing homes, the only controlled evaluation of efforts to influenza vaccination coverage among HCWs, suggests that publicity and educational messages about the importance of vaccination are only effective when combined with other approaches to increase coverage. The results of the interventions conducted by the Minneapolis VAMC and Mayo Clinic indicate that combining free vaccination with programs to increase vaccine accessibility by using either mobile carts or peer vaccination can overcome certain barriers to HCW influenza vaccination. These findings were supported by a recent cross-sectional evaluation of interventions for HCWs in neonatal and pediatric intensive-care units and hematology-oncology units (7) that demonstrated that use of mobile carts and educational materials were associated with higher vaccination rates. The Mayo Clinic intervention suggests that additional incentives might increase coverage further.

The results described in this report are consistent with other studies demonstrating that organizational change (e.g., separate clinics devoted to prevention), free vaccine, and gift incentives are particularly effective methods of increasing vaccination among adults (8,9). Interventions that were used to increase coverage among HCWs, including standing orders and reducing out-of-pocket costs, both in conjunction with education, are consistent with interventions strongly recommended by the Task Force on Community Preventive Services (9).

The findings in this report are subject to at least two limitations. First, ascertainment of vaccination status in the southern California study was based on self-report, and only 61% of HCWs responded. Second, the VAMC and Mayo Clinic studies did not control for other factors that might have increased influenza vaccination; none of the studies were able to determine what proportion of HCWs had risk factors other than their status as HCWs that might have put them at increased risk for influenza and its complications. Nonetheless, each of the interventions described in this report resulted in vaccination rates exceeding national averages.

The influenza vaccine shortage during the 2004--05 season might have prevented health-care institutions from implementing aggressive campaigns for vaccination of HCWs. However, HCWs remain a high-priority group for vaccination (5). The National Foundation for Infectious Diseases has produced a call to action to improve rates of influenza vaccination in HCWs (10). The interventions described in this report suggest that making vaccination easily accessible at no cost to HCWs and designated peer vaccination champions are likely to increase vaccine coverage among HCWs.


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  10. National Foundation for Infectious Diseases. Influenza vaccination among health care workers. Bethesda, MD: National Foundation for Infectious Diseases; 2004. Available at

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