Both Paxlovid and molnupiravir have been shown to reduce hospitalization and death from Covid-19 if taken early on in the course of an infection. “They are most effective when used within a few days of the onset of symptoms,” Dr. Gandhi said.
In a Pfizer trial published in December and conducted before the Omicron wave, Paxlovid reduced the risk of hospitalization and death in high-risk, unvaccinated people by 88 percent when given within five days of symptom onset.
Molnupiravir, however, has been shown to be less effective. One analysis from Merck, also published in December, showed that it reduced the risk of hospitalization and death in high-risk, unvaccinated adults with Covid-19 by only 30 percent if taken within five days of symptom onset.
Because of this lower efficacy, Dr. Gandhi said that “most clinicians, including myself, prefer Paxlovid if it’s available and if a person doesn’t take any other medications that make Paxlovid a problem for them.”