Optimism is boosted by leaders hoping for job creation, increased business spending, and a high consumption rate. In this research, we assessed the hazardous side effect for global health policies stemming from this optimism: unrealistic optimism (being unrealistically optimistic about future negative events), which may be responsible for new infections and may prevent the eradication of COVID-19. The goal of the research was not only to assess whether this effect exists and to find out whether such an effect is global but also to evaluate whether there are groups resistant to this effect (presenting a potential toolkit for reducing this effect).

Material and methods:
In May and April of 2020, online surveys were administered among students in Iran, Kazakhstan, and Poland respectively to assess the unrealistic optimism/pessimism. In study 1/objective 1, the survey was conducted twice (in a period of about 3 weeks) to assess the potential change (due to the anonymous codes delivered by the participants, we were able to make follow-ups between the same participants) in time in the 3 countries. In the first wave, 1611 participants took the survey. In the second wave, there were 1426 respondents. In study 2, the survey was conducted among 207 Polish healthcare workers of the frontline hospital.

In study 1 across the 3 cultures (the first wave for unmatched data by the code of the specific participant F(1, 1608) = 419.2; p < 0.001, and for matched data F(1, 372) = 167.195; p < 0.001; ηp² = 0.31; ηp² = 0.21; the second wave for unmatched data F(1, 1423) = 359.61; p < 0.001; ηp² = 0.2, and for matched F(1, 372) = 166.84; p < 0.001; ηp² = 0.31), unrealistic optimism is present, and importantly it is constant in time. In study 2, unrealistic optimism was not found among healthcare professionals, who we hypothesized due to the medical knowledge are not inclined to be unrealistically optimistic t(206) = 1.06; p = 0.290, d = 0.07.

Medical education of COVID-19 severity might reduce unrealistic optimism, which may be the reason why pandemic restrictions are not being respected.