The European Union's drug regulator conditionally approved the use of Pfizer Inc's antiviral Covid-19 pill for treating adults at risk of severe illness, as the region scrambles to boost its arsenal to fight the highly infectious Omicron variant, Reuters reports.

Pfizer's two-drug regimen called Paxlovid, which is meant to be taken at home for five days soon after the onset of Covid-19 symptoms, was authorised for people aged 12 and older by the US Food & Drug Administration in December.