WASHINGTON (NewsNation Now) — President Joe Biden’s administration is contracting with a digital diagnostics company to make the country’s first over-the-counter, at-home COVID-19 test accessible to more Americans.

White House coronavirus adviser Andy Slavitt announced in a Monday briefing that the government awarded a $231-million contract to Ellume to scale up production of its rapid antigen test. The Australian manufacturer’s at-home test was granted an emergency use authorization from the Food and Drug Administration in December.

For months, health experts have stressed the need for fast, widespread home testing so that people can screen themselves and avoid contact with others if they have an infection. But the vast majority of tests still require a nasal swab performed by a health worker that must be processed at high-tech laboratories.

Ellume’s test kit allows users to swab themselves at home and check their status in about 20 minutes. It also includes a smartphone app that provides instructions explaining how to take a nasal swab and place it into the small analyzer that processes the sample. The app connects to the analyzer via Bluetooth to display the test results on the user’s phone.

It’s one of only three tests that consumers can use themselves, and the only one available without a doctor’s prescription.

Ellume said Monday it would use the contract to construct a U.S. manufacturing plant and deliver 8.5 million tests for federal use. It did not specify a timeframe for delivery.

Also at the White House COVID-19 response team’s briefing Monday, Dr. Anthony Fauci stressed the importance of getting vaccinated as quickly as possible, “when it becomes available.”

“The reason for that, is that there is a fact that permeates virology and that is, that viruses cannot mutate if they don’t replicate. And if you stop their replicating by vaccinating widely and not giving the virus an open playing field to continue to respond to the pressures that you put on it, you will not get mutations,” he said. “So, when we’re looking at what we have here in the United States as well as globally, when we talk about efficiently and getting these vaccines out there into people as quickly as we possibly can, not only are you going to prevent individuals from getting disease, not only are you going to protect them from getting infected, but you are going  to prevent the emergence of variants here in our country.”

The briefing was held hours before a mask mandate on U.S. public transportation takes effect.

The Centers for Disease Control and Prevention issued an order Friday requiring masks in interstate transportation and at transit hubs, including airplanes, mass transit, taxis and trains.

The CDC said the mask mandate, effective from Monday at 11:59 p.m. EST, also covers ride-share vehicles and subways and makes not wearing a mask as instructed a violation of federal law. The CDC directive follows an order from President Joe Biden on Jan. 21 directing agencies to “immediately take action” to require masks on transportation and at transit hubs.

“Requiring masks on our transportation systems will protect Americans and provide confidence that we can once again travel safely even during this pandemic,” the order stated. “Therefore, requiring masks will help us control this pandemic and aid in reopening America’s economy.”

Fauci warned that with the emergence and increasing spread of coronavirus mutations, vaccine makers must be ready to make new shots to stay ahead of the public health crisis.

“This is a wake-up call to all of us,” he said, noting government scientists will be working to keep pace with virus mutations.

The South Africa virus variant was first discovered in the U.S. in South Carolina Thursday. Other variants first reported in the United Kingdom and Brazil were previously confirmed in the U.S. 

Nearly 50 million vaccine doses have been distributed across the United States with more than 31.1 million doses administered, according to the CDC. The United States has more than 26.1 million confirmed coronavirus cases with more than 441,000 Americans dead from the virus, according to data compiled by Johns Hopkins University.

The Associated Press and Reuters contributed to this report.