US biopharmaceutical company Pfizer Inc (NYSE:PFE) and its German partner BioNTech SE (Nasdaq:BNTX) said on Monday that a third shot of their COVID-19 vaccine has been shown to be effective in young children.

In a Phase 2/3 trial which took place at a time when Omicron was the predominant variant, vaccine efficacy was 80.3% in children aged 6 months to under 5 years of age.

A total of 1,678 children took part in the trial, receiving a third shot of the low-dose formulation at least two months after their second shot.

Pfizer and BioNTech plan to submit the new data to the US Food and Drug Administration (FDA) this week, with submissions to the European Medicines Agency (EMA) and other regulators to follow.