
So far, vaccines from Pfizer Inc, Moderna Inc and Johnson & Johnson have been authorised for emergency use in the US.
Novavax Inc has had discussions with regulators and said it does not expect to seek regulatory authorisation for its Covid-19 shot in the US, Britain and Europe until the third quarter of 2021.
Canadian drug developer Medicago said it was in discussions with the FDA for an EUA for its plant-based Covid-19 vaccine candidate, which is enhanced by a GlaxoSmithKline treatment.
AstraZeneca also has discussed plans for its Covid-19 vaccine with US officials.
However, the Wall Street Journal earlier this month reported that it was considering skipping US emergency-use authorisation and instead pursue the more time-intensive application for a full-fledged licence to sell the shot.
AstraZeneca and Novavax did not immediately respond to requests for comment.