Johnson & Johnson's coronavirus vaccine enters Phase 3 trials, becomes fourth in U.S. to reach mark

Johnson & Johnson says its coronavirus vaccine will on Wednesday enter Phase 3 of clinical trials, making it the fourth company to start such large-scale trials in the U.S. 

As many as 60,000 adult participants will receive the single dose vaccine in the United States and other countries, a Johnson & Johnson official said on a call with reporters.

The three other pharmaceutical companies with trials in the U.S. are AstraZeneca, Moderna and Pfizer/BioNTech. 

The coronavirus pandemic is now in its seventh month.

The Johnson & Johnson's vaccine candidate is a single-dose vaccine, while the others are a double dose, according to CNN.