Background:As a response to the COVID-19 pandemic outbreak, strict national policies regarding public behavior were implemented in countries throughout the world, including Europe, America and Australia. Social distancing became the main policy for public behavior, in effect imposing radical changes in people’s everyday life. Thus, mental health may be affected at the general population level and not only among those who have been infected by the disease or have witnessed family members or close ones fall ill.Methods:A cross-sectional online survey was conducted in Norway, UK, USA and Australia during April/May 2020. Participants (n = 3810) were recruited via social media postings by the researchers and the involved universities. Differences between those with and without infection in the family were investigated with chi-square tests and independent t-tests. Multiple regression analyses were used to assess associations between sociodemographic variables and psychological outcomes (worry, loneliness and mental health) in both groups.Results:Compared to their counterparts, participants with infection in the family reported higher levels of worries about themselves (p < 0.05) and their family members (p < 0.001), and had poorer mental health (p < 0.05). However, the effect sizes related to the differences were small. The largest effect (d = 0.24) concerned worries about their immediate family. Poorer psychological outcomes were observed in those who were younger, female, unemployed, living alone and had lower levels of education, yet with small effect sizes.Conclusions:In view of the small differences between those with and without infection, we generally conclude that the mental health effects of the COVID-19 situation are not limited to those who have been infected or have had infection within the family, but extend to the general population.