The Omicron variant could cause tens of thousands of deaths in England by the end of April if additional virus restrictions are not imposed, new modelling suggests.
Researchers said the new variant, which is expected to be more transmissible, could cause 24,000 deaths by 30 April 2022 in the most optimistic scenario and nearly 75,000 deaths in the most pessimistic scenario.
"In our most optimistic scenario, the impact of Omicron in the early part of 2022 would be reduced with mild control measures such as working from home," said Dr Rosanna Barnard from the London School of Hygiene & Tropical Medicine who co-led the research.
"However, our most pessimistic scenario suggests that we may have to endure more stringent restrictions to ensure the NHS is not overwhelmed. Mask-wearing, social distancing and booster jabs are vital, but may not be enough," said Barnard in a statement.
In the two scenarios, the team estimated that the Omicron variant would be between 10% less transmissible than the Delta variant to 35% more transmissible than Delta.
The Delta variant is currently widespread throughout Europe and has caused the latest surges across the continent.
The World Health Organization classified Omicronas a "variant of concern" last month due to its large number of concerning mutations.
The UK Health Security Agency has said that studies of contacts of Omicron show that it is transmitting more effectively than the Delta variant.
They estimate that it could become the dominant strain of the virus, accounting for more than 50% of all COVID-19 infections by mid-December.
The most pessimistic scenario analysed by the researchers showed a peak in hospital admissions in England around twice as high as seen in January 2021.
"These are early estimates, but they do suggest that overall Omicron is outcompeting Delta rapidly by evading vaccines to a substantial degree," said Dr Nick Davies, also from the school's Centre for the Mathematical Modelling of Infectious Diseases.
The research by the modellers has not yet been reviewed by other experts in the field and was published in pre-print.
Prime Minister Boris Johnson announced several new virus measures this past week, bringing in a vaccine pass for access to nightclubs and large events.
The government will also reintroduce guidance to work from home from Monday.
If no additional measures beyond this are implemented, there could still be 2,000 daily hospital admissions in the most optimistic scenario, researchers said on Saturday.