%S TSE Working Paper %A Nicolas Treich %A François Salanié %T Public and private incentives for self-protection %X Governments sometimes encourage or impose individual self-protection measures, such as wearing a protective mask when going outside during an epidemic. However, by reducing the risk of being infected by others, more self-protection may lead each individual to go outside more often. In the absence of lockdown, this creates a “collective offsetting effect”, since more people outside means that the risk of infection is increased for all. Yet, wearing masks also creates a positive externality on others, by reducing the risk of infecting them. We show how to integrate these different effects in a simple model, and we discuss when self-protection efforts should be encouraged (or deterred) by a social planner. %B TSE Working Paper %V 20-1090 %D 2020 %C Toulouse %I TSE Working Paper %L publications34707