Factorial Design for Improving Influenza Vaccination Among Employees of a Large Health System

OBJECTIVE. As healthcare personnel (HCP) influenza vaccination becomes a quality indicator for healthcare facilities, effective interventions are needed. This study was designed to test a factorial design to improve HCP vaccination rates. DESIGN. A before-after trial with education, publicity, and free and easily accessible influenza vaccines used a factorial design to determine the effect of mobile vaccination carts and incentives on vaccination rates of HCP, who were divided into groups on the basis of their level of patient contact (ie, business and/or administrative role, indirect patient contact, and direct patient contact). SETTING. Eleven acute care facilities in a large health system. PARTICIPANTS. More than 26,000 nonphysician employees. RESULTS. Influenza vaccination rates increased significantly in most facilities and increased system-wide from 32.4% to 39.6% (P <.001). In the baseline year, business unit employee vaccination rates were significantly higher than among HCP with patient contact; rates did not differ significantly across groups in the intervention year. In logistic regression that accounted for demographic characteristics, intervention year, and other factors, the use of incentives and/or mobile carts that provided access to vaccine at the work unit significantly increased the likelihood of vaccination among HCP with direct and indirect patient contact, compared with control sites. CONCLUSIONS. Interventions to improve vaccination rates are differentially effective among HCP with varying levels of patient contact. Mobile carts appear to remove access barriers, whereas incentives may motivate HCP to be vaccinated. Education and publicity may be sufficient for workers in business or administrative positions. Interventions tailored by worker type are likely to be most successful for improving HCP vaccination rates.