Novavax Inc's COVID-19 vaccine is effective in generating an immune response against the Omicron variant, and an additional booster dose produces further immune resistance to the new variant, according to early data published on Wednesday.

Novavax said the data was taken from its ongoing studies of its vaccine's effectiveness in adolescents and as a booster.

Novavax's two-dose, protein-based vaccine was authorized for use this week by European Union regulators and the World Health Organization. It has previously been approved by countries including Indonesia and the Philippines but not the United States.

Novavax is working on developing an Omicron-specific vaccine and said Wednesday it expects to begin manufacturing doses of the variant-specific shot in January.

The drugmaker will start shipping vaccines to the EU's 27 member states in January as part of its deal to supply up to 200 million doses.

The company will also begin shipments in early 2022 to COVAX, a vaccine distribution mechanism overseen by WHO that allocates COVID-19 shots to poorer countries. Novavax and its partner, Serum Institute of India, have agreed to send COVAX more than 1.1 billion doses of Novavax's vaccine.