J&J’s single-shot vaccine could help boost supply and simplify the US immunisation campaign, which continues to lag behind schedule.

Johnson & Johnson said on Thursday it has asked United States health regulators to authorise its single-dose COVID-19 vaccine for emergency use.

The drugmaker’s application to the US Food and Drug Administration (FDA) follows its January 29 report in which it said the vaccine had a 66 percent rate of preventing infections in its large global trial.

J&J’s single-shot vaccine could help boost supply and simplify the US immunisation campaign, amid concerns of fresh surges due to the more contagious UK coronavirus variant and the potential of lower vaccine efficacy against the variant that first emerged in South Africa.

Unlike the two currently authorised vaccines from Pfizer Inc/BioNTech SE and Moderna Inc, J&J’s does not require a second shot or need to be shipped frozen.

After the company’s application, regulators will need time to analyse the data and an advisory committee will need to meet. The company’s chief scientific officer said last month J&J was on track to roll out the vaccine in March.

J&J’s application raised hopes for fighting the pandemic that has killed more than 451,145 Americans and more than 2,271,152 worldwide.

Shares of Johnson & Johnson, Moderna and Pfizer were little changed in after-hours trade.

The US has an agreement to buy 100 million doses of J&J’s vaccine for $1bn, and the option of buying an additional 200 million doses.

The company has said it has doses ready for delivery upon emergency approval. It aims to deliver one billion doses in 2021 with production in the US, Europe, South Africa and India.

J&J’s vaccine uses a common cold virus known as adenovirus type 26 to introduce coronavirus proteins into cells in the body and trigger an immune response.

The Pfizer/BioNTech and Moderna vaccines use a new technology called messenger RNA (mRNA) that requires it to be stored in a freezer.