The EU's drug regulator approved use of the COVID-19 vaccine from U.S.-based Novavax Monday (December 20) in people aged 18 and older, making it the fifth shot to be approved in the region which is currently grappling with a record surge in infections.

The European Medicines Agency said data from two large studies showed the vaccine has an efficacy of around 90%.

It did add that there was currently limited data on its efficacy against some variants of concern though, including Omicron.

The regulator said, quote, ''the data on the vaccine were robust and met the EU criteria for efficacy, safety and quality.''

The endorsement for the two-dose vaccine comes well ahead of possible authorization in the United States, where Novavax has had to resolve manufacturing issues and expects to file for approval by the end of the year.

The regulatory process in the EU has taken longer than expected, too.

The European Medicines Agency started a rolling review of the data back in February.

Novavax said on Monday it would start shipping vaccines to the EU's 27 member states in January.