Johnson & Johnson's one-shot COVID-19 vaccine has been given formal approval by U.S. regulators, making it the third jab available in the country.
The go-ahead was given a day after a committee of independent experts delivered their endorsement of the vaccine to the U.S. Food and Drug Administration (FDA).
The approval is a boost for U.S. vaccine efforts, which have been picking up speed after a sluggish rollout. About 47.2 million people have received at least one dose of a COVID-19 vaccine, the Centers for Disease Control and Prevention said on Friday.
New Jersey-based Johnson & Johnson said 20 million doses would be delivered in the U.S. by the end of March. The company plans to deliver 100 million doses during the first half of 2021.
The doses can be stored in a standard fridge, unlike the ultra-cold conditions required by the other two vaccines from Moderna and Pfizer/BioNTech, both of which are two-shot regimes.
A global clinical trial showed the Johnson & Johnson vaccine was 66- percent effective at preventing various coronavirus variants. It was 80 percent effective at protecting against severe cases.