解釋見內

https://www.yalemedicine.org/news/13-things-to-know-paxlovid-covid-19

“You have to take Paxlovid within five days of developing symptoms.

Like all antivirals, Paxlovid works best early in the course of an illness—in this case, within the first five days of symptom onset, says Jeffrey Topal, MD, a Yale Medicine infectious diseases specialist who is involved in determining COVID-19 treatment protocols for Yale New Haven Hospital patients.

“Once you’ve been ill with the virus for more than a week, the damage done to the body in a severe case can’t be undone by the antiviral,” he says.”