LAUSR

The coronavirus (severe acute respiratory syndromecoronavirus 2 [SARS-CoV-2], coronavirus disease 2019 [COVID-19]) pandemic has caused over 88 million confirmed cases and nearly 2 million deaths worldwide as of December 2020. Months ago, governments launched unprecedented responses in an attempt to contain the staggering health and economic threats. In most countries, emergency state declarations with strict confinement and quarantine regulations were followed by phased reopening, emphasizing adherence to public health recommendations regarding hand washing, use of masks, and social distance. However, the situation has continued to evolve, and we are witnessing an increase in the number of cases in many regions of the world. We believe addressing this increase in COVID-19 cases and preventing further waves of the present pandemic particularly as the first vaccines begin to be offered, requires understanding and addressing optimism bias. Optimism bias refers to the mistaken belief that our chances of experiencing negative events are lower than predicted or than those faced by our peers. Such optimism can be beneficial by reducing stress, controlling anxiety, and promoting physical health. However, dealing with the pandemic requires behavioral changes, adherence to precautions, and adoption of personal hygiene practices that may be uncomfortable and cumbersome. Similarly, early acceptance of vaccine harbors some uncertainties. Individuals with excessive optimism bias are less likely to follow such recommendations if they perceive their individual risk to be low, which not only puts them, but all of us in danger. Data from the international research and analytics group YouGov (https://yougov.co.uk) reveal that all around the world, people are more worried about the potential health impact of COVID-19 on others than on themselves. There are, however, striking differences across countries (Fig 1). On average, in the United States, people are about 15% more worried about the health impact of COVID-19 for others than for their own health, in Europe the average difference is 22%, whereas in the Far East countries it is only 9%. Notably, the disparity in concerns for self versus others across countries is not significantly correlated with the absolute level of fear for self (ρ = −0.15; p = 0.46) or for others (ρ = 0.23; p = 0.27), and is relatively stable across time. This suggests a deeper relation of the disparity in concerns for self versus others with cultural differences. Cultures can be divided into collectivists and individualists. Individualist cultures, such as those of Europe or the United States, emphasize personal achievement and individual rights even at the expense of group goals. Collectivist culture, such as those of Japan, Korea, or China, emphasize group goals above individual needs or desires. Such cultural differences influence neural activity, for example, in the medial prefrontal cortex, and can thus impact the processing of self-related information and decision making. Further relevant insights can be obtained from the Barcelona Brain Health Initiative (BBHI), a longitudinal cohort study assessing genetic, biological, and lifestyle determinants of brain health. A total of 3,326 individuals (1,955 women; mean age 54.2 7.1 years) completed web-based questionnaires in up to 4 time-points, March 20 to 22, April 1 to 3, May 4 to 6, and June 1 to 3, 2020, approximately 1, 3, 7, and 11 weeks following the decree of a national state of emergency and a strictly enforced lock-down mandate by the Spanish government. As part of our questionnaires, participants were asked about their worries regarding their own health and that of their family and friends. Consistent with the YouGov’s results, BBHI participants reported being much more worried about the health impact of COVID-19 on others than on themselves. Figure 2 summarizes the findings across time relating them to the severity of the pandemic in Spain at the time of the various assessments. The difference of over 30% in people’s concerns about the health of others than their own was present also among BBHI participants with one or more risk factors for COVID-19 related morbidity and mortality (including age older than 60 years, preexisting obesity, diabetes or cardiovascular disease, and smokers). Similarly, the