Willingness to pay for influenza vaccination among the elderly in Vietnam: A triple-bounded dichotomous choice analysis of economic and behavioral determinants.

BACKGROUND

Seasonal influenza causes significant morbidity among the elderly, yet vaccination remains an out-of-pocket expense in Vietnam. This study evaluated the willingness to pay (WTP) for influenza vaccination and its determinants among the elderly in Vietnam.

METHODS

A community-based cross-sectional study was conducted in Can Tho City, Vietnam (N = 1486). We employed the Contingent Valuation Method with a Triple-Bounded Dichotomous Choice framework. Data were analyzed using multivariable logistic regression to identify predictors of WTP and interval regression to estimate the mean WTP and its monetary determinants.

RESULTS

Overall, 54.9% of participants expressed a WTP, but only 28.9% were willing to cover the full market cost. The estimated mean WTP was 12.08 USD (95% CI: 11.66-12.50). Logistic regression revealed that vaccine hesitancy was the strongest predictor; non-hesitant individuals were 13.71 times more likely to express WTP (p < 0.001). Other significant predictors included high income (aOR = 2.22), medical recommendations (aOR = 1.80),and diabetes mellitus (aOR = 1.41). Interval regression showed that vaccine hesitancy "devalued" the vaccine by approximately 30%, with highly hesitant individuals willing to pay 4.12 USD less than those with low hesitancy. Conversely, media exposure increased the WTP amount by 1.10 USD. Most respondents (66.1%) identified the state budget as the preferred financial support source.

CONCLUSIONS

A significant affordability gap exists for influenza vaccination among the Vietnamese elderly. While financial subsidies are necessary to support low-income groups, they must be paired with communication strategies to reduce vaccine hesitancy. We recommend a subsidized co-payment model (minimum 4-5 USD subsidy per dose) and leveraging healthcare provider recommendations to enhance vaccine valuation and uptake.