previous coverage before it was approved, explaining the superiority

* https://www.theatlantic.com/health/archive/2023/10/xocova-en...

* https://nypost.com/2023/10/26/health/why-covid-sufferers-in-...

Differences in Treatment Patterns and Patient Characteristics Between COVID-19 Patients Treated with Nirmatrelvir/Ritonavir and Ensitrelvir in Japan

* https://pmc.ncbi.nlm.nih.gov/articles/PMC11345459/