UK researchers have analysed the likely impact that a Covid booster shot will have on Omicron and say it could provide around 85% protection against severe illness.
The protection is a bit less than vaccines gave against earlier versions of Covid.
But it means the top-up dose should still keep many people out of hospital.
It comes as a record 861,306 number of booster jabs and third doses were given in the UK on Thursday. (Foreign Agencies)