Valuing the benefit of varicella vaccination: comparison of willingness to pay and quality-adjusted life-years

Vaccination is different from most health interventions because it is preventative, it protects against infectious disease (leading to knock-on effects), the diseases it prevents are usually acute and self-limiting, and most vaccines are given to children from whom it is very difficult to elicit preferences. Because of its unique characteristics, vaccination may possess its own specific attributes. In this paper, we estimate the average Willingness to Pay (WTP) for varicella vaccination and the Quality-Adjusted Life-Years (QALY) lost due to chickenpox using Contingent Valuation (CV), Standard Gamble and Health Utility Index Mark II (HUI2). Furthermore, we identify what attributes of vaccination are important to vaccinees and what elicitation technique can capture these components. To do this, we administered computerised interviews to a sample of parents attending primary Health Centres. Using CV we demonstrate that individuals are willing to pay more for vaccination than treatment. Furthermore, we show that prevention of work loss is an important intervention attribute for parents. On the other hand, consistent with economic theory, the elicitation techniques used to estimate QALYs (Standard Gamble and HUI2) did not capture non-health benefits. Finally, results elicited using the CV were correlated with QALYs measured through the HUI2 questionnaire