Johnson & Johnson stock rocketed up 7% in early Monday trading after the company announced its experimental coronavirus vaccine could be used for human testing by September—and possibly approved under emergency authorization by early 2021.

“Based upon our early data, we feel confident that we have got a very good candidate,” Johnson & Johnson CEO Alex Gorsky told Fortune.

J&J's COVID-19 vaccine sprang from a partnership with the Biomedical Advanced Research and Development Authority (BARDA), an arm of the federal Department of Health and Human Services. The two groups have pledged $1 billion toward coronavirus vaccine development.

Gorsky said the vaccine also came from a development platform the company had invested in a decade ago. “The underlying technology turn out to have much broader application than we anticipated,” he said.

Johnson & Johnson hopes to move into early-stage trials by the fall, gathering initial data by the end of the year, and have doses available for wider use by early 2021 under a Food & Drug Administration (FDA) emergency use authorization.

To prepare for that possibility, Gorsky said the company is also significantly scaling up its manufacturing capabilities for the coronavirus vaccine candidate.

“For us to have an impact in a meaningful time, we have to start ramping up our production. That’s what we are doing in the U.S.,” he said.

As for pricing? The company says that its vaccine would be provided affordably to the public “on a not-for-profit basis for emergency pandemic use.”