Trust in Informal information seems to be associated with less perceived susceptibility to health threat. This may reflect rational processes or cognitive bias. Trusting social cues involves comparison and conformity influences, and can enhance optimistic bias (the tendency to view oneself less likely to experience negative events but more likely to experience positive events) in personal risk estimates [56] , thereby reducing perceived Susceptibility. Conversely, others' behavioural cues about health threat proximity can arouse motivating worry and anxiety producing protective action [17, 29] . We found Trust in informal information was independent of both Understanding of influenza cause and Self-efficacy. However, when stratified by gender, the Trust in informal information-Understanding association was positive among males but negative among females. Education is probably an important influence in understanding and may have a bearing on these patterns which await clarification.