The Food and Drug Administration's staff endorsed Johnson & Johnson's Covid-19 vaccine for emergency use, a critical step in bringing a third shot to the U.S.

The FDA staff said it determined that the clinical trial results and safety data were "consistent with the recommendations set forth in FDA's guidance Emergency Use Authorization for Vaccines to Prevent COVID-19.".

5, there were seven Covid-19 related deaths in the study in the placebo group and no Covid-19 related deaths in the vaccine group, the FDA said.

If approved, J&J's application would be the third Covid-19 vaccine authorized for emergency use in the U.S.

Pfizer's vaccine was authorized on Dec.

The company has said it plans to ship the vaccine, which contains five doses per vial, at 36 to 46 degrees Fahrenheit.

By comparison, Pfizer's vaccine needs to be stored in ultra-cold freezers that keep it between minus 112 and minus 76 degrees Fahrenheit.

Pfizer's vaccine was found to be 95% effective against preventing Covid-19, while Moderna's was found to be about 94% effective.