Pfizer’s New Covid Treatment Pill: U.S. Seeks ‘Urgent’ Data on Covid Relapses After Using the Drug. Health & Medicine 04 May 2022 Researcher says Covid symptoms returned days after use of Pfizer's Paxlovid. Rebound cases have Read more Pfizer’s New Covid Treatment Pill: U.S. Seeks ‘Urgent’ Data on Covid Relapses After Using the Drug.