The United States is purchasing an additional 10 million courses of Pfizer's COVID-19 treatment Paxlovid, the company said Tuesday, bringing the total U.S. order to 20 million. 

The move comes as the Biden administration seeks to ramp up the treatments available as another tool to battle the virus.

Pfizer also said Tuesday that the delivery of the first 10 million courses has been accelerated to June, with the following 10 million coming by September. 

Experts have been pushing the White House to do more to ramp up production of the treatment given that it can play a major role in defanging the virus, but it is expected to be in shortage in the near term.

The White House previously said that just 265,000 courses of the treatment would be available in January, amid a major surge of COVID-19.

Officials have pointed to a complex manufacturing process as posing hurdles to getting doses sooner. 

"It’s still way too small and too late to meet the anticipated needs," Eric Topol, professor of molecular medicine at Scripps Research, wrote in an email after the announcement of the new order.  

President Biden is set to give remarks on the omicron variant and the latest in the response to the surge later Tuesday afternoon. 

Pfizer did not give a price for the latest order of its treatment. The U.S. paid $5.295 billion for the original 10 million courses. 

Trials showed that the pill is highly effective, reducing the risk of hospitalization or death by 89 percent in high-risk patients. It is intended to be taken within five days of the onset of symptoms.