A shift from consensus-based to uncertainty-based messaging by the CDC regarding vaccines and autism significantly alters public perception, increasing perceived risks and reducing trust.
Study Overview
A recent policy article by Bohm et al. details a large-scale online experiment investigating how different communication styles from the U.S. Centers for Disease Control and Prevention (CDC) affect public attitudes and behaviors.
The study involved 2,989 U.S. adult participants who were randomly assigned to read either a consensus-based or an uncertainty-based CDC-style statement about the link between vaccines and autism.
Key Findings
The results show that the uncertainty-based message had a clear and measurable impact on participants:
- Increased Perceived Vaccine Risks: Participants exposed to the uncertainty message reported higher levels of perceived risk associated with vaccines.
- Reduced Vaccination Intentions: The same group showed a lower willingness to vaccinate themselves or their families.
- Lowered Trust in the CDC: Trust in the public health institution decreased among those who read the uncertainty-based statement.
- Increased Endorsement of Science-Denial Strategies: The uncertainty message was linked to a greater acceptance of strategies that reject scientific consensus.
These effects were observed consistently across the political spectrum, indicating that the impact of uncertainty-based messaging is not limited to a specific ideological group.
Implications for Public Health
The authors underscore the critical responsibility of public health institutions. Communicating scientific uncertainty, while sometimes necessary, must be done in a way that protects population health and preserves institutional trust. The study suggests that the framing of uncertainty can inadvertently undermine public health goals.