Public health emergencies have seriously affected the tourism industry. Meanwhile, one critical indicator of review quality, travelers' online review efforts, requires special research attention. This study takes the COVID-19 pandemic as an example in exploring how this crisis can influence hotel travelers' online review efforts and the underlying mechanism. Using a mixed-method design that includes secondary and experimental data analysis, the study results reveal that travelers' emotional expressions mediate the pandemic's impact on online review efforts. Specifically, the pandemic makes emotional expressions more negative, thereby reducing online review efforts. Furthermore, cognitive expressions moderate the above mediating effect such that the higher one's cognitive expression is, the weaker the mediating effect. This study also provides theoretical and practical implications.