WASHINGTON (BLOOMBERG) - Johnson & Johnson will deliver about 2 million doses of its Covid-19 vaccine when it receives an emergency use authorisation in the US, according to a Government Accountability Office report published Thursday (Jan 28).

The figure revealed in a footnote to the government audit is the clearest indication yet of the initial supply of Johnson & Johnson's one-shot vaccine.

A spokesman for Johnson & Johnson said in an email that it expected to supply 100 million doses to the US government in the first half of the year. He didn't comment further on the GAO report.

The company was expected to have doses available in the single-digit millions by the second half of February, Moncef Slaoui, the top scientific adviser to the Trump administration's vaccine development effort, said earlier this month.

"We're trying to make that number get as close to a double digit number as possible," Slaoui said at a briefing at the time.

Johnson & Johnson is expected to report clinical-trial data on the experimental shot's efficacy by early next week, Chief Financial Officer Joseph Wolk told Bloomberg in a Jan 26 interview. The company aims to have seven manufacturing facilities running by the end of the second quarter to ramp up supply, Wolk said.