Effect of familiarity with COVID-19 infection--history of infection or close contact--on outing behaviors when a state of emergency is declared

MORI, T.; Nagata, T.; Ikegami, K.; Hino, A.; Tateishi, S.; Tsuji, M.; Matsuda, S.; Fujino, Y.; Mori, K.

Background: Restricting the movement of the public to gathering places and limiting close physical contact are effective measures against COVID-19 infection. In Japan, states of emergency have been declared in specific prefectures to reduce public movement and control COVID-19 transmission. We investigated how familiarity with the COVID-19 infection affected self-restraint related to outing behaviors during state of emergency declarations in Japan. Methods: A prospective cohort study was conducted among workers aged 20-65 years using data from an internet survey. The baseline survey was conducted on December 22-25, 2020, and a follow-up survey was on February 18-19, 2021. There were 19,941 participants who completed both surveys and were included in the final analysis. We set self-restraint regarding outing behaviors after the second state of emergency was declared in January 2021 as the dependent variable, and levels of familiarity with COVID-19 infection as independent variables. Odds ratios were estimated using multilevel logistic analyses. Results: Significant differences by familiarity with COVID-19 infection were identified: compared with people without a history of COVID-19 or close contact with cases of confirmed COVID-19, and those whose acquaintances had not been diagnosed with COVID-19, people with a history of COVID-19 did not refrain from most outing behaviors. People with an acquaintance diagnosed with COVID-19 were significantly more likely to refrain from most outing behaviors. There was no significant difference in any outing behavior for people with a history of close contact only. Conclusions: To maximize the effect of emergency declarations, health authorities should disseminate information for each person in the target population, taking into account potential differences related to the familiarity with the infection.