Perceived risks of adverse effects and influenza vaccination: a survey of hospital employees.

BACKGROUND Many hospital employees shun influenza immunization because they want to avoid adverse reactions. We surveyed hospital employees to elucidate whether the conception of the adverse effects of vaccination stems from correct or misperceived incidence rates of vaccine adverse effects.  METHODS We used an anonymous self-administered paper questionnaire at a tertiary-care university hospital in Germany, in 2006. Multiple-choice questions probed respondents' knowledge about influenza, influenza vaccine and about rates of 12 possible vaccine adverse effects. We correlated overestimation of each adverse effect with failure to obtain vaccination in 2005-06, stratified by professional group.  RESULTS The overall response rate was 34% (652/1898). Of the 304 respondents unvaccinated in 2005-06, 127 (42%) attributed their vaccination status mainly to concerns about adverse effects. Among physicians, failure to obtain influenza vaccination was associated with the overestimation of both non-severe and severe adverse effects. Non-vaccinated nurses were significantly more likely than the vaccinated nurses to overestimate the rates of five of six non-severe adverse effects, but differed significantly in rates of overestimation of merely one of the six severe adverse effects. Overestimation of vaccine-caused absenteeism from work was negatively associated with vaccination rates among all professionals.  CONCLUSIONS Overestimation of the actual low rates of influenza vaccine adverse effects was associated with non-receipt of the vaccine among hospital employees. Due to our finding of different misconceptions about adverse effects, educational and promotional programmes should be targeted differentially for nurses and physicians.