Background: Several research studies have examined the reasons why people are hesitant to be vaccinated against COVID-19. However, there is no published data to date on Switzerland. Identifying these reasons among the Swiss population who are vaccine hesitant may help inform campaigns to encourage vaccine confidence.Aims: The primary aim of this study is to identify the reasons for not getting vaccinated against COVID-19 among Swiss residents who are vaccine hesitant. The secondary aim is to examine whether reasons differ by age, gender, education, and likelihood of accepting a vaccination to better target campaigns and design interventions.Design: An online survey asked participants to indicate the reasons why they were hesitant to be vaccinated against COVID-19. Setting: German-speaking Swiss Cantons, the survey was administered online between 5 May 2021 and 16 May 2021.Participants: The participants in this analysis were a sample of (N=1191) Swiss residents age 16-60 years old from German-speaking Cantons, who could answer an online survey in German, who had yet not been vaccinated, who had not yet registered for a vaccination appointment, and who did not indicate that they would definitely be vaccinated if offered the chance.Findings: Among people who are vaccine hesitant in Switzerland, the most common reasons for being hesitant were side-effect, safety, and effectiveness concerns. It was also common for people to indicate that they were healthy/at low risk, would decide later, and that they wanted to build immunity naturally. Less common, but still prevalent concerns included wanting more information, thinking COVID-19 was not a real threat, and concerns that the vaccine may serve another purpose. Differences in reasons for being vaccine hesitant were found by age, gender, education, and likelihood of accepting a vaccination if offered.Conclusions: To increase the likelihood of accepting a vaccination, vaccination campaigns should address side-effect, safety, and effectiveness concerns. Campaigns could also consider informing people why it is necessary for people in lower risk groups to be vaccinated, and why vaccination is preferable to infection for building immunity. While campaigns may be effective in reaching some of the population, alternative strategies might be necessary to strengthen the trust relationship with vaccines and vaccine providers in some groups. Less prevalent concerns, such as not liking needles, could be addressed through individual level interventions.

Background Behavioural, environmental, social and systems interventions (BESSIs) remain important for controlling the COVID-19 pandemic in addition to vaccination. However, people’s adoption of BESSIs may decrease as vaccination rates increase due to reductions in the perceived threat of disease, and changes in risk perceptions of behaviours that increase the chance of infection. Thus, we examined predictors of and changes over time in reports of mask wearing and physical distancing and whether changes in mask wearing and physical distancing differed by vaccination status during the main 2021 COVID-19 vaccine roll-out period in Switzerland. Methods Weekly online cross-sectional surveys (26 April 2021 to 1 August 2021) among people 18–79 years old in Switzerland, N = 6308 observations and 5511 cases. Logistic regression models using generalized estimating equations. Results Reports of being vaccinated increased, while mask wearing and physical distancing decreased over time. This decrease was similar regardless of vaccination status. However, the level of reported mask wearing and physical distancing remained higher among vaccinated people. Older, female, and Italian language region respondents also had higher odds of reporting mask wearing and physical distancing. Conclusions Adoption of COVID-19 preventive behaviours is associated with demographics and vaccination status. Further research is needed to understand the reasons why people who are not vaccinated are less likely to adopt preventive behaviours, including that they may have fewer social and environmental opportunities to do so.

Social norms messages may motivate COVID-19 preventive behaviors, such as getting vaccinated. To date, however, the research has mainly focused on the established concept of static norms and widely ignored the potential of dynamic norms. Dynamic norms convey information about how norms are developing over time and have been shown to promote change when the behavior is not yet the majority norm. The present study investigated the potential of dynamic norms in the context of the COVID-19 vaccination campaign. It examined (a) the effects of static and dynamic norms messages on vaccination intention, (b) the mechanisms through which dynamic norms may influence vaccination intention, and (c) the potential of dynamic norms to increase vaccination intention of vaccine-hesitant people. We conducted a preregistered online experiment with three conditions (static norm, dynamic norm, control message) among people who were not yet vaccinated (N = 2,289, 16-60 years) in May 2021, during the early vaccine roll-out period for the general population in Switzerland. We found no effects of exposure to the static or dynamic norms messages on vaccination intention and no specific influence mechanisms of dynamic norms (e.g., via perceived future norm) - neither for participants who were willing to get vaccinated nor for the vaccine-hesitant group. However, further analyses showed that, among vaccine-hesitant participants, the normative perception that formerly vaccine-critical people were changing their minds was correlated with a stronger vaccination intention. We discuss potential reasons why social norms messages did not show an effect in our study and derive theoretical and practical implications.