Johnson & Johnson's Covid-19 vaccine trial is now fully enrolled

 Johnson & Johnson said Thursday that its late-stage Covid-19 vaccine trial is fully enrolled.

The vaccine, made by J&J subsidiary Janssen, comes in a single dose. The trial now has about 45,000 participants. 

The company said with the high rate of disease transmission among the general population in the United States, this number of volunteers should be enough to quickly get the data the company needs to determine if the vaccine works and to determine if it is safe.

J&J expects to have interim data by the end of January.

If the trial goes as expected, the company said it expects to submit the trial results to the US Food and Drug Administration for an emergency use authorization in February.