WHO approves? Relative trust, the WHO, and China's COVID-19 vaccines.

This paper aims to answer a general question: whether an international organization (IO) is able to shape public opinion in the context of the COVID-19 pandemic. Since the pandemic took hold in early 2020, countries across the globe have switched gear from prevention to vaccination. Most had to not only secure a sufficient supply of vaccines, but also to curb vaccine hesitancy among their populations. Can endorsement by an international organization like the World Health Organization (WHO) enhance a vaccine's acceptability? Based on a survey experiment conducted in Taiwan, our study leverages the special relationship between China and Taiwan to show that WHO endorsement can induce acceptance of Chinese vaccines among Taiwanese people. However, the effect is found to be contextual in the sense that it only works when people's trust in the WHO is higher than their trust in the vaccine's country of origin. Our study not only contributes to the literature of IO legitimacy by empirically showing IOs' causal effects on public opinion, but also sheds light on how a vaccine's credibility can be enhanced to promote vaccination uptake. Supplementary Information: The online version contains supplementary material available at 10.1007/s11558-022-09481-1.