U.S. health officials announced today that a third COVID-19 shot will be available beginning the week of Sept. 20 for all Americans who were fully vaccinated with either the Pfizer or Moderna vaccines. The recommendation arises out of concern over the delta variant surge and data suggesting immune protection from vaccination may fade over time. Individuals would receive this third shot — of their original vaccine — about eight months after receiving their second dose. Details regarding third doses for WashU Med employees and students will be forthcoming.