Shares of Altimmune (NASDAQ:ALT) surged 35.4% over the past week, coinciding with a dramatic shift in retail investor sentiment on Reddit. The clinical-stage biotech develops treatments for metabolic diseases and became one of the highest-rated stocks in social sentiment tracking after the FDA granted Breakthrough Therapy Designation for its lead drug pemvidutide on January 16. Mentions of Altimmune on Reddit increased sharply, with users sharing high-conviction positions.