In a letter on Sunday, Capitol Physician Brian Monahan shared the changes with lawmakers returning to Washington this week. 

"Individuals may choose to mask at any time, but it is no longer a requirement," he wrote.  

Monahan said positive COVID-19 test rates at the Capitol are down to 2.7 percent in the last two weeks, below the current rate for the DC-Metropolitan area (4.7 percent). 

The Washington, D.C. area is a 'green level,' according to Centers for Disease Control and Prevention (CDC) metrics, meaning that COVID-19 transmission is low. 

The CDC on Friday eased its mask recommendation for most Americans, advising that people living in communities with "low" or "medium" COVID-19 levels can go maskless. 

Monahan said other "coronavirus risk reduction measures" would remain in place for the State of The Union address, "with the exception that, KN95 or N95 mask wear is no longer required and mask wear is now an individual choice option." 

Nine U.S. states have lifted their mask mandates in recent weeks, many with Democratic governors, who have cited the recent decrease of COVID-19 cases. 

The House had been following a mask mandate since July, in line with guidance from the CDC at the time to limit the spread of the virus. The Senate never adopted a mask mandate. 

House Speaker Nancy Pelosi (D) has largely deferred to Monahan on COVID-19 measures on the House floor.