Why using fear to promote COVID-19 vaccination and mask wearing could backfire You probably still remember public service ads that scared you: The cigarette smoker with throat cancer. The victims of a drunk driver. The guy who neglected his cholesterol lying in a morgue with a toe tag. With new, highly transmissible variants of SARS-CoV-2 now spreading, some health professionals have started calling for the use of similar fear-based strategies to persuade people to follow social distancing rules and get vaccinated. There is compelling evidence that fear can change behavior, and there have been ethical arguments that using fear can be justified, particularly when threats are severe. As public health professors with expertise in history and ethics, we have been open in some situations to using fear in ways that help individuals understand the gravity of a crisis without creating stigma.