How Does the Public Evaluate Vaccines for Low-Incidence, Severe-Outcome Diseases? A General-Population Choice Experiment.

Background: Because immunizing large numbers of healthy people could be required to reduce a relatively small number of infections, disease incidence has a large impact on cost effectiveness, even if the infection is associated with very serious health outcomes. In addition to cost effectiveness, the US Advisory Committee on Immunization Practices requires evidence of stakeholders' values and preferences to help inform vaccine recommendations. This study quantified general-population preferences for vaccine trade-offs among disease severity, disease incidence, and other vaccine features.

Methods: We developed a best-practice discrete choice experiment survey and administered it to 1185 parents of children aged 12-23 years and 1203 young adults aged 18-25 years from a national opt-in consumer panel. The data were analyzed using exploded-logit latent-class analysis.

Results: Latent-class analysis identified two classes with similar relative-importance weights in both samples. One of the two classes represented about half the samples and had preferences consistent with well-structured, logically ordered, and acceptably precise stated-preference utility. Preferences for the other half of the samples were poorly defined over the ranges of vaccine and disease attributes evaluated. Both parents and young adults in the first class evaluated protection from a disease with 1 in 100 incidence and full recovery at home as having statistically the same preference utility as a disease with 1 in 1 million incidence requiring hospitalization and resulting in permanent deafness.

Conclusions: The results suggest that vaccines that protect against low-incidence, severe-outcome diseases, provide 'peace of mind' benefits not captured by standard health-outcome metrics. The fact that half the respondents had poorly defined vaccine preferences is a reminder of the challenges of implementing patient-centric vaccine decision making.