BioNTech and Pfizer said on Wednesday a three-shot course of their Covid-19 vaccine was able to neutralise the new Omicron variant in a laboratory test, an early signal that booster shots could be key to protection against infection from the newly identified variant.

The German and US companies said two doses of their vaccine resulted in significantly lower neutralising antibodies but could still be protective against severe disease.

"The first line of defence, with two doses of vaccination, might be compromised and three doses of vaccination are required to restore protection," BioNTech Chief Medical Officer Ozlem Tuereci said at a press conference...