The U.S. government is buying 100 million doses of Moderna Inc.'s COVID-19 treatment as part of a $1.5 billion deal, President Donald Trump says.

The medication is currently undergoing advanced-phase human tests. Moderna will test its safety and effectiveness in 30,000 participants. The biotech company has said it could have results for its third-stage trials in two months.

If approved Moderna will produce and deliver 100 million doses to fight infections in the U.S., the Health and Human Services Department said in a statement.

The Massachusetts-based pharmaceutical company said separately the contract for its experimental mRNA-1273 treatment was valued at $1.53 billion. The government has an option to buy 400 million more doses, it said. Moderna's late-phase clinical tests, which began July 27, is the first government-financed, third-stage clinical test for an experimental COVID-19 medication.

Moderna has already received more than $955 million in funding from the government for its vaccine program. To date the U.S. has spent almost $2.5 billion with Moderna.

The government has also bought initial batches of COVID vaccines from Novavax, Sanofi and GlaxoSmithKline, Pfizer, Johnson & Johnson, AstraZeneca and Moderna as part of its Operation Warp Speed.

Warp Speed is the administration's program to make vaccines available once granted federal approval. HHS said the objective was to find a safe treatment by the end of 2020.

The U.S. government will own Moderna's production of the drug. "We are buying them," Trump said at the White House on Tuesday.

The administration's latest efforts are making it more possible that the U.S. can avail itself of "at least one safe and effective vaccine" by 2021, HHS Secretary Alex Azar said.