The Kansas City Federal Reserve Bank last week scrapped plans to gather at the foot of the Tetons outside Jackson Hole, Wyo., for its annual economic policy conference amid rising concerns about health threats posed by the Delta variant—a reminder of how the Covid-19 pandemic continues to pose considerable uncertainty for the U.S. economy despite the broad availability of highly effective vaccines.

Instead, Fed policy makers and outside academics are set to gather online Friday for the second straight virtual symposium. The theme of this year’s event is “Macroeconomic Policy in an Uneven Economy.”

The event kicks off at 10 a.m. Eastern time with remarks on the economic outlook by Fed Chairman Jerome Powell. The central bank is in the middle of a heated debate over how and when to begin dialing back its extraordinary stimulus, including $120 billion in monthly asset purchases.

Investors are looking for clues from Mr. Powell over whether the Delta variant has altered plans to begin scaling back, or tapering, those purchases in coming months.