ABSTRACT
Immunization is recognized as the most cost-effective way of preventing and controlling diseases. Many childhood vaccines recommended by the World Health Organization have been listed as non-NIP (National Immunization Program) vaccines in China. Individuals have to pay fully out-of-pocket for the shots and the uptake is voluntary. Despite the severe disease burden of the related diseases, coverage rates have been low due to the expensive prices of these vaccines, particularly for underserved areas. This study focused on childhood Varicella and PPV13 vaccines. We aim to identify financing and promotion strategies that effectively promote parental preferences for the two vaccines.
We conducted a discrete choice experiment in Jiangsu, Guizhou and Qinghai provinces during July to August 2020. Areas were selected to present different economic development levels. Parents of children under six were invited to participate in the experiment at point-of-visits. For Varicella vaccines, our design of attributes and levels included efficacy (50%, 70%, or 90%), , adverse event incidence (0.1%, 0.05%, or 0.01%), protection duration in years (3, 5, or 10), time of visits (1, or 2), total costs (RMB) (100, 200, or 400), the choice of friends (yes, or no), can be financed by the personal account of insurance (yes, or no). For PPV13 vaccines, our design is generally similar to that of the Varicella vaccines except that we did not include the time of visit attribute, modified levels of total costs (RMB) (700,1400, or 2800), and added international products (yes, or no). A sequential orthogonal factorial design was used to extract a set of 48 paired comparisons, which were then randomly divided into 3 sets of 16 questions. The sets of questions were randomly distributed to the participants. In each question, the participants were required to select a preferred vaccine and then asked whether they were willing to immunize their children with the selected vaccine.
A total of 578 and 606 parents participated in the Varicella vaccine and the PPV13 vaccine experiments, respectively. We used a mixed logit model to fit the choice results. We found that parents were more preferred to the vaccine that was chosen by their friends, suggesting a strong herd behavior in immunization decision making. For Varicella vaccines, the public was willing to pay on average additional 102,17 RMB for the product that was chosen by their friends. In contrast, we only found that such attributes only significantly improved parental preferences for PPV13 vaccines in more developed Jiangsu province. Allowing individuals to pay for vaccination costs via their personal account of health insurance was expected to resulted in 4-6 percentage points increase in uptake rates. The effect of such financing policy was estimated to be much smaller than a direct reimbursement via government subsidies.