Researchers at Utah State University performed research to show that xylitol blocked viral adhesion on human airway tissue. Though a similar study was performed previously using industry standards (performed on vero kidney tissue), the FTC required a higher-standard study to show efficacy. This study using that higher standard, shows that xylitol and other sugar alcohols block adhesion of different viruses to different degrees.
Jung, Kie Hoon. (2021). Antiviral Efficacy Against Virus Infections in Human-Derived Tracheal/Bronchial Epithelial Cells. Utah State University.