Willingness to pay for allergy-vaccination among Danish patients with respiratory allergy

Objective: The aim of this study was to elicit willingness to pay (WTP) for allergen-specific subcutaneous injection immunotherapy (SCIT) in a cohort of respondents suffering from allergic-rhinoconjunctivitis (a-RC)/asthma, and to investigate how patients self-select to SCIT according to need. Methods: A random sample of the general population was screened for a-RC/asthma and asked if they were willing to consider SCIT. They were asked to state their WTP for SCIT by way of a discrete choice question (DC-q), an open-ended WTP question (o-WTP-q), and questions relating to their sociodemographic background and the severity of their a-RC/asthma. The characteristics of respondents demanding SCIT were compared with the characteristics of respondents who have actually received SCIT to establish possible barriers to demand. Results: Our results suggest that respondents do well in self-selecting themselves to SCIT on the basis of need according to disease burden measured in terms of a-RC classification, number of contacts with a general practitioner, number of sick days, and potential quality-adjusted life-year loss. Mean WTP for SCIT was estimated at €655 (median, €267) (o-WTP-q) and €903 (95 percent confidence limit, 348–1,459) (DC-q). Conclusion: Characteristics of respondents, who consider SCIT and are willing to pay for SCIT, suggest that allergy sufferers select themselves appropriately according to need and not according to other characteristics, such as income or education. There is a significant discrepancy between those who hypothetically consider SCIT and those demanding SCIT in real life. This study suggests that there are barriers to entry related to age and education, but not to income.