Background: Distrust of COVID-19 vaccines may hamper vaccination campaigns. We focused on the cognitive determinants of intentions to get vaccinated against COVID-19. We were interested in (i) the effects of stress, and (ii) the effects of self-protection systems on attitudes and intentions to get vaccinated with a COVID-19 vaccine. Methods: We conducted an online observational study with 203 French students (MAge = 19, SDAge = 2.52, Women = 173), in which we measured, through self-reported questionnaires, their perceived stress and vulnerability to disease, belief in a dangerous world, pandemic-related stressors living conditions, attitudes and intentions to get vaccinated, and confidence in the government's management of COVID-19. We conducted two multiple linear mediation analyses.Results: Participants who reported higher trust in the government and who reported higher stress levels were more likely to have positive attitudes toward the COVID-19 vaccine, although both these influences seem to be –at least partially - independent. Conclusions: The factor that most robustly predicted both attitudes and intentions to vaccinate was confidence in the information provided by the government and its ability to manage the pandemic in general. Our analyses suggest the existence of two profiles of people likely to have positive attitudes toward vaccination: those who trust the government and are not stressed by vaccination, and those who do not trust the government but would get vaccinated to reduce their stress. We discuss how to improve the effectiveness of COVID-19 vaccine policies through communication.

Literature shows that intolerance of uncertainty can negatively affect health professionals' medical decision-making process. However, there is no intolerance of uncertainty measurement tools in French, so this study aimed at validating the Intolerance of Uncertainty Scale-12 (IUS-12) in French, and a version of the IUS-12 adapted for healthcare professionals (IUS-12-H). We asked health professionals to complete our two scales of interest, as well as several scales covering related constructs. Five hundred and sixteen health professionals completed French versions of the IUS-12 and the IUS-12-H, and our additional scales. Exploratory factor analyses showed that the IUS-12 and IUS-12-H scales had a two-factor structure as in the seminal article of Carleton et al. (2007). The IUS-12 and the IUS-11-H French versions show psychometric properties comparable to the original version indicating that they can be used as the seminal scales for French health professionals.