My local news just said Fauci would be appearing with a mask, but it looks like they will all testify remotely:
"Dr. Anthony Fauci, the nation's leading infectious diseases expert, will testify before a Senate committee Tuesday, his first appearance before Congress since March. Fauci will appear alongside Dr. Robert Redfield, the director of the Centers for Disease Control and Prevention (CDC), and other officials to discuss reopening the economy amid the coronavirus pandemic.
Senator Lamar Alexander, the chairman of the Senate Health, Education, Labor and Pensions (HELP) Committee, announced Sunday that the committee hearing would take place over video conference.
"After consulting with Dr. Fauci, and in an abundance of caution for our witnesses, senators, and the staff, all four Administration witnesses will appear by videoconference due to these unusual circumstances," Alexander said in a statement. Food and Drug Administration Commissioner Stephen Hahn and Assistant Secretary for Health Brett Giroir will also appear at the virtual hearing."
cbsnews.com/news/dr-anthony-fauci-to-testify-before-senate-subcommittee-about-coronavirus-response/