Mealey's (April 11, 2023, 9:29 AM EDT) -- NEW ORLEANS — Responding to the contention of a group of physicians made to the Fifth Circuit U.S. Court of Appeals that a Texas federal court erred in ruling that the Food and Drug Administration had sovereign immunity from suit for its public pronouncements concerning the use of ivermectin for the treatment or prevention of COVID-19, the government in its responsive brief argues that the narrow ultra vires exception to sovereign immunity could not apply because the challenged acts of the FDA were informational only and not without any authority whatsoever or without any colorable basis....