Six months after regulators issued an emergency use authorization for Paxlovid, physicians say they still have significant questions about prescribing guidelines for the leading treatment for high-risk Covid patients.

STAT spoke with providers who said they and their colleagues aren’t on the same page about when to prescribe Paxlovid or the criteria that separates those who need it from those who do not. They also said it is unclear whether they can give a second course when patients test positive again after taking Paxlovid, a phenomenon known as a rebound.

And nearly all the experts who spoke with STAT said that they are clamoring for more data on rebounds, which is complicating and sometimes changing their calculus about when to give the drug. “There is a real dearth of evidence right now out there, and obviously there’s a lot of confusion,” said Jonathan Li, a physician at Brigham and Women’s Hospital and virology researcher at Harvard Medical School who is also a member of the Covid-19 Treatment Guidelines Panel.

Read more at STAT News