In recent history, four influenza pandemics have occurred causing worldwide suffering. It is only a matter of time when a fifth pandemic will emerge. The willingness of the public to perform recommended precautionary actions is central for successful outbreak management, where the most important measure is vaccination. Trust in the health care system as well as personal perceptions of the threat of a pandemic can influence the publics willingness to perform precautionary actions. Aims: This study seeks to analyze how the public in two socioeconomically different areas of Stockholm perceive the threat of a possible future epidemic, their level of trust in the health system and what precautionary actions they are willing to perform. Methods: questioners with respondents from two socioeconomically different areas in Stockholm (Tensta and Danderyd) were gathered and have been statistically analyzed and interpreted using the health belief model and theories about trust. Results: The study showed that a higher level of perceived benefits of precautionary actions and a higher level of worriedness to get seriously ill if infected during an influenza epidemic were correlated with a higher level of willingness to follow precautionary actions. A significant association between unwillingness to vaccinate and perceived barriers to vaccination (that it can be harmful to the health) was also found. Trust in the health system was significantly lower in Tensta compared to Danderyd and higher trust in the health system was found to lead to higher perceived benefits of precautionary actions. Additionally, respondents with higher trust in information from the health care were generally more willing to vaccinate. Finally, no demographic determinants except age was shown to influence perceptions about precautionary actions and threat. Conclutions: Willingness to perform precautionary actions were influenced by worriedness, perceived benefits, perceived barriers, age and trust in the health care. Efforts might thus be needed to increase the trust in the health system in socioeconomically weak areas, as well as to increase the trust in influenza vaccination in general.