Novavax Inc said on Monday it would pursue full approval of its COVID-19 vaccine in the second half of this year and forecast total revenue of between $4 billion and $5 billion for 2022.

"We expect to gain additional authorizations where we have already filed, including in the U.S. We will pursue full approval of our vaccine including filing our BLA (biologics license application), in the second half of 2022," Chief Executive Officer Stanley Erck said during a post-earnings call.

Novavax late last month filed for emergency use authorization of the shot in U.S. adults, a much-awaited step following months of struggles with development and manufacturing problems.

Novavax said it has completed delivery of around 9 million vaccine doses to Indonesia, 6 million to Australia and 2 million to South Korea and expects to supply 69 million doses to Europe in the first half of this year.

The company earlier forecast to send 2 billion COVID-19 shots around the world in 2022.

Novavax on Monday did not disclose how many doses it expects to deliver in the first quarter, but forecast $4 billion to $5 billion in overall revenue in 2022. Analysts had forecast $4.70 billion in revenue.

A big chunk of the revenue would be through product sales, and of that the vast majority is related to vaccine product sales, the company said.

Separately, Novavax said an extended analysis of a late-stage study conducted in the United Kingdom showed that its COVID-19 vaccine provided long-term protection against the coronavirus.

The protein-based vaccine, NVX-CoV2373, continued to provide protection and maintained overall efficacy of 82.7% over a six-month period.

Novavax is working on developing an omicron-specific vaccine and said on Monday it expects to begin manufacturing doses of the shot at a commercial scale in the first quarter.