Does face mask use elicit risk-compensation? Quasi-experimental evidence from Denmark during the SARS-CoV-2 pandemic

Background: Public use of face masks has been widely adopted to halter the SARS-CoV-2 pandemic, but a key concern has been whether the effectiveness of face mask use is limited due to the elicitation of false feelings of security that decrease the observance of other protective behaviors, the so-called risk-compensation. Methods: We exploit quasi-experimental variation, prompted by three major changes in policy, to assess whether public use of face masks elicit risk-compensation by increasing the number of close contacts or decreasing attention to distancing and hygiene measured in daily nationally representative surveys (N = 106 880). Results: Number of close contacts: Face mask use prompted by the policy changes decrease the number of contacts in two of the three interventions. In the remaining intervention, it has no effect. Attention to hygiene: Across the changes, face masks use does not affect people's attention to hygiene. Attention to distancing: In two of three interventions, face mask use increase attention to distancing. In the remaining intervention, we see a decrease in attention. Conclusions: Overall, public use of face masks may occasionally elicit a narrow form of risk-compensation; specifically, reducing engagement in physical distancing. However, such narrow forms of risk-compensation are limited: The results do not reveal any effects on the actual number of physical contacts, only on the psychological attention to distancing advice. Moreover, the negative effect only appears for one of three interventions. The other two interventions suggest that face mask use increases attention to physical distancing.