Aims: In response to the 2009 outbreak of A/H1N1 influenza, Swedish authorities decided on a programme for universal vaccination. Over 60% of the population received at least one dose of vaccine. This study examines demographic factors and perceptions related to the decision whether or not to become vaccinated. Methods: A combined web/postal survey was conducted (n = 1587, response rate 53%) in late spring 2010. Questions reported here concerned perceptions, precautionary behaviours and vaccination decision. Results: Main reasons for becoming vaccinated were concerns about spreading the disease to relatives or in the community and confidence in the good effect of vaccination. Vaccination rates were higher among women, those with young children or belonging to a risk group. Main reasons for abstaining were belief that the flu was not a serious threat, low risk of spreading the disease, concern about side-effects and perceived uncertainties in information. Three profiles representing different patterns of thought and beliefs were identified by cluster analysis, respectively labelled as a vulnerable, a trusting and a sceptical group. Vaccination rates and precautionary behaviours were demonstrated to differ between these groups. Conclusions: Perceptions relating to the 2009 pandemic are likely to influence uptake of vaccination in the future. Authorities need to be aware of different patterns of beliefs and attitudes among the public, and that these may vary in different phases. Communication of risk needs to be dynamic and prepared to engage with the public before, during and even for some time after the acute risk period. [ABSTRACT FROM PUBLISHER]