In the fourth section, household demand was collected.For example, the first
WTP question was framed as: “Suppose that the total cost for the dengue fever vaccine would
be VND 450,000 for three dose needed for one person. Would you buy this vaccine for your
youngest child?” To access household WTP, the additional question was followed: “Suppose
that this dengue fever vaccine costs VND 450,000 for the 3-dose series required for each person
(same price for adults and children), how many people in your household (not including your
youngest child) would you be willing to purchase vaccines for?. . .Who would you buy this vaccine
for?” The responses were recorded in a table which is linked to the demographic information
in the first section.