Two new studies have suggested catching Omicron is less likely to result in severe symptoms and hospital admission than earlier Covid strains like Delta.
But Professor Neil Ferguson from the Imperial College London team behind one of the studies, warned Omicron’s severity may be offset by the “reduced efficacy” of vaccines to stop it being transmitted.
The new data was released after Boris Johnson faced calls to outline his post-Christmas Covid strategy for England, as Northern Ireland, Wales and Scotland have all announced new restrictions to tackle the Omicron variant.
Recorded case rates of Covid across the UK rose above 100,000 on Wednesday for the first time since the start of the pandemic.
New research from Imperial College London has indicated that people with PCR-confirmed Omicron are 15-20% less likely to need admission to hospital, and 40-45% less likely to require a stay of one night or more.
Scientists in a separate Scotland-wide study called Early Pandemic Evaluation and Enhanced Surveillance of Covid-19 have said Omicron is associated with a two-thirds reduction in the risk of hospital admission compared with Delta.
However, researchers have added that although Omicron appears less severe, it is more transmissible partly because the current crop of coronavirus vaccines are less effective against it.
Prof Ferguson said: “Our analysis shows evidence of a moderate reduction in the risk of hospitalisation associated with the Omicron variant compared with the Delta variant.
“However, this appears to be offset by the reduced efficacy of vaccines against infection with the Omicron variant.
“Given the high transmissibility of the Omicron virus, there remains the potential for health services to face increasing demand if Omicron cases continue to grow at the rate that has been seen in recent weeks.”
Both studies are yet to be peer-reviewed, with Dr Jim McMenamin, the national Covid-19 incident director for Public Health Scotland, labelling the findings of the Scotland study a “qualified good news story”.