https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9087011/#!po=49.1379
我总结一下文章的意思：
1）用药十天也是安全的。2）但模型显示五天十天效果一样. 3）用药五天后，大概相当于感染九天后，病毒动力学主要由清除过程来决定，而药物阻断的病毒复制相对来说不重要了。所以药厂用五天作为疗程。
（我不了解新冠病毒在体内复制清除过程，只是照搬文章内容。）
In fact, QSP modeling predicted that 5 days of dosing of oral nirmatrelvir/ritonavir 300/100 mg b.i.d. would demonstrate meaningful antiviral effect, supporting this duration for phase II/III trials. Dosing for > 5 days in symptomatic patients was predicted to have no additional benefit. The physiological rationale for this observation is that after 5 days of dosing (~ 9 days after symptom onset and about 2 weeks after infection 25 , 36 , 37 ) viral dynamics may be almost entirely driven by viral clearance rates, and not by viral replication.
