In healthcare workers, a 2006 review found a net benefit. Of the eighteen studies in this review, only two also assessed the relationship of patient mortality relative to staff influenza vaccine uptake; both found that higher rates of healthcare worker vaccination correlated with reduced patient deaths. A 2014 review found benefits to patients when healthcare workers were immunized, as supported by moderate evidence based in part on the observed reduction in all-cause deaths in patients whose healthcare workers were given immunization compared with comparison patients where the workers were not offered vaccine.