WASHINGTON -- Johnson & Johnson said on Monday it had selected a lead candidate vaccine for the new coronavirus that would move to human trials by September and could be ready for emergency use by early next year.

The pharmaceutical company has signed an agreement with the U.S. government's Biomedical Advanced Research and Development Authority to invest US$1 billion in the effort, it said in a statement.

J&J began working on the investigational vaccine, Ad26 SARS-CoV-2 in January using the same technology it used to develop a candidate vaccine for Ebola.

It uses a deactivated version of the virus to try to trigger a human immune response.

The company said it was expanding its global manufacturing capacity both in the US and in other countries, to help it supply more than a billion doses of its vaccine around the world.

CEO Alex Gorsky said the company was "well positioned through our combination of scientific expertise, operational scale and financial strength to bring our resources in collaboration with others to accelerate the fight against this pandemic."

J&J is also working on antiviral treatments against the coronavirus.

Separately, the U.S. pharmaceutical Moderna has already moved into human trials for its vaccine candidate, as has China's CanSinoBIO.

There are currently no approved vaccines or treatments for the disease.

Several treatments are being investigated, including the antiviral remdesivir and antimalarial drugs chloroquine and hydroxychloroquine, but it is not yet clear whether they add anything to standard care.