AstraZeneca, the drugmaker that developed one of the first COVID-19 vaccines, has asked the U.S. Food and Drug Administration to authorize the emergency use of a first-of-a-kind antibody treatment to prevent the disease. The Anglo-Swedish company said Tuesday that the treatment, known as AZD7442, would be the first long-acting antibody combination to receive an emergency authorization for COVID-19 prevention. If authorized, the drug would likely be limited to people with compromised immune systems who don’t get sufficient protection from vaccination. “First and foremost we want to protect those vulnerable populations that haven’t been adequately protected by the vaccine,” said Menelas...