DHODH and influenza: In addition to the in vitro observations, Xiong et al. [15] have shown that the DAA oseltamivir was primarily effective in the early phase of influenza A virus infection in an influenza mouse model (i.e., within 48 h of symptom onset), while DHODH inhibitors may also be effective when treatment was started in middle-to-late phases of influenza disease [15].