of influenza vaccination in children was only 31%. Higher rates were found among immuno-suppressed pediatric patients (46%), and in patients with inflammatory bowel disease (50%). Adults In unvaccinated adults, 16% get symptoms similar to the flu, while about 10% of vaccinated adults do. Vaccination decreased confirmed cases of influenza from about 2.4% to 1.1%. No effect on hospitalization was found. In working adults, a review by the Cochrane Collaboration found that vaccination resulted in a modest decrease in both influenza symptoms and working days lost, without affecting transmission or influenza-related complications. In healthy working adults, influenza vaccines can provide moderate protection against virologically confirmed influenza, though such protection is greatly reduced or absent in some seasons. In health care 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 health care worker vaccination correlated with reduced patient deaths. A 2014 review found benefits to patients when health care workers were immunized, as supported by moderate evidence based in part on the observed reduction in all-cause deaths in patients whose health care workers were given immunization compared with comparison patients where the workers were not offered vaccine. Elderly Evidence for an effect in adults over 65 is unclear. Systematic reviews examining both randomized controlled and case–control studies found a lack of high-quality evidence. Reviews of case–control studies found effects against laboratory-confirmed influenza, pneumonia, and death among the community-dwelling elderly. The group most vulnerable to non-pandemic flu, the elderly, benefits least from the vaccine. There are multiple reasons behind this steep decline in vaccine efficacy, the most common of which are the declining immunological function and frailty associated with advanced age. In a non-pandemic year, a person in the United States aged 50–64 is nearly ten times more likely to die an influenza-associated death than a younger person, and a person over 65 is more than ten times more likely to die an influenza-associated death than the 50–64 age group. There is a high-dose flu vaccine specifically formulated to provide a stronger immune response. Available evidence indicates that vaccinating the elderly with the high-dose vaccine leads to a stronger immune response against influenza than the regular-dose vaccine. A flu vaccine containing an adjuvant was approved by the US Food and Drug Administration (FDA) in November 2015,