Health communication about truly novel diseases (TNDs) (e.g. COVID-19) poses a challenge. TNDs are marked by uncertainty: while the chances of contracting the disease are certain, the health consequences of the disease remain uncertain. This study aims to focus on these two aspects of disease, disease probabilities (i.e. chances of contracting a disease) and disease consequences (i.e. associated symptoms), and examines their influence on information seeking and preventative behavior such as vaccination. In addition, the authors examine the role of emphasis framing on consumers’ preventative behavioral intentions. This research advances the theoretical understanding of health communication for TNDs and provides communication guidelines for policymakers and health-care marketers.