A team of UK researchers has analysed the likely impact that a Covid booster shot will have on Omicron and says it could provide around 85 per cent protection against severe illness.

According to the BBC, the protection is a bit less than vaccines given against earlier versions of Covid. But it means the top-up dose should still keep many people out of the hospital.

The modelling, from the team at Imperial College London, is based on limited information on Omicron.

The researchers said there is a high degree of uncertainty until more real-world information is gathered about this new variant that is spreading quickly.

Experts are still trying to figure out how mild or severe Omicron will turn out to be, the report said.

Vaccines help teach the body how to fight Covid. But the current ones in use were not designed to combat the heavily-mutated Omicron variant, meaning they are not a perfect match.

To get around that, people in the UK are being advised to have a booster dose to build up higher antibody levels to fight the virus.