Privacy concerns can explain unwillingness to download and use contact tracing apps when COVID-19 concerns are high.

Governments around the world have increasingly relied on technology to promote public health, such as using electronic health records and portable fitness devices. During the COVID-19 pandemic, "contact tracing apps" for smartphones have also been promoted in many countries as a way to allow public officials to facilitate contact tracing. But uptake in virtually all countries where such apps have been promoted is slow, one reason being privacy concerns. Conducting three experiments across France ( = 471), Australia ( = 202), and the United States ( = 1005), we explore if salient COVID-19 concerns, which intuitively should increase concerns about personal and public health, might in fact increase privacy concerns and thereby reduce uptake of contact tracing apps. Using an experimental design where we randomly assign participants to either a disease concerns or control condition, we find that salient COVID-19 concerns decrease intentions to download contact tracing apps. Mediation results reveal that greater valuations of privacy explain the lower willingness. We therefore explain why COVID-19 contact tracing apps that are promoted when the pandemic is at its peak see low levels of uptake. Our results provide policy makers with implications concerning how to promote uptake to help "flatten the curve" of not just the current pandemic but potentially also future ones.