Researchers in Japan reveal that personal experience with the virus heightens awareness of "silent infection," leading to more consistent preventive behavior

Osaka, Japan - Researchers at The University of Osaka have found that individuals in Japan who have been infected with COVID-19 are more likely to wear masks than those who have not. In a four-year-long study, they discovered this change is not driven by fear, but by a heightened perception of the risk of "silent infection,” the idea that one could be infected and spread the virus without knowing. This insight could reshape public health messaging for future pandemics.

During a pandemic, preventive behaviors like hand washing and mask-wearing are crucial. However, the impact of personal infection experience on these behaviors has been inconsistent; does it make people more cautious or more complacent? To find a clearer answer, this study used a statistical method called propensity score matching. This technique allowed researchers to compare infected and non-infected individuals who were matched on their pre-infection attitudes, behaviors, and demographics, thereby isolating the true effect of the infection experience itself.

The research team analyzed data from a 30-wave panel survey of adults in Japan (2020–2024). After matching 135 pairs of individuals, they found that 94.8% of those who had been infected with COVID-19 continued to wear masks, compared to 87.4% of their uninfected counterparts. The infected group also reported a higher perceived risk of being unknowingly affected by the virus. A statistical analysis confirmed that the infection experiences increased mask-wearing *through* this heightened awareness of "silent" or asymptomatic risk.

This study suggests that public health campaigns could be more effective by incorporating the authentic experiences of those who have been infected. Instead of just issuing guidelines, messages that convey the realization that "anyone could be a silent carrier" may resonate more deeply with the public. By translating the felt experience of patients into relatable lessons, health officials can better encourage preventive actions in the general population and improve preparedness for future health crises.

Lead author Professor Michio Murakami states, “Experience shapes perception, which in turn drives behavior. We found that even after recovering, people don't abandon preventive actions. The realization that ‘I could be infected without noticing’ sustains their cautious behavior. Translating the genuine experiences of patients into relatable messages for the public is key to preparing for the next infectious disease outbreak.”
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The article, “The impact of COVID-19 infection experience on risk perception and preventive behaviour: a cohort study,” was published in Epidemiology & Infection at DOI: https://doi.org/10.1017/S0950268825100940

About The University of Osaka
The University of Osaka was founded in 1931 as one of the seven imperial universities of Japan and is now one of Japan's leading comprehensive universities with a broad disciplinary spectrum. This strength is coupled with a singular drive for innovation that extends throughout the scientific process, from fundamental research to the creation of applied technology with positive economic impacts. Its commitment to innovation has been recognized in Japan and around the world. Now, The University of Osaka is leveraging its role as a Designated National University Corporation selected by the Ministry of Education, Culture, Sports, Science and Technology to contribute to innovation for human welfare, sustainable development of society, and social transformation.
Website: https://resou.osaka-u.ac.jp/en