It's Your Most Precious Thing: Worst-case thinking, trust, and parental decision making about vaccinations

Vaccines are often heralded as one of the greatest success stories of modern medicine. Yet public concerns have surfaced recently, in part because of the declining incidence of many target diseases, but also in response to increasing questions about safety. Public health messages designed to encourage vaccination often assume that parents are unaware of the risks and consequences of the diseases; that those who harbor doubts or reservations about vaccine safety are irrational, emotional, or laboring under misconceptions; or that skeptics are being manipulated by a well-orchestrated campaign by antivaccination groups. This project explores how parents assess probabilistic information on vaccine risks and benefits and what may drive them to consider some possible outcomes as worst cases, leading them to deviate from official recommendations. Semistructured interviews with 20 parents indicate that parents employ both probabilistic and possibilistic thinking, but that the contextual factors that influence their interpretation of that information vary. Trust is an especially important contextual factor; parents struggling with vaccination decisions describe the importance of trust at multiple levels-in the vaccine, in their doctor, and in the broader public health policy network.