The coronavirus variant that emerged in the United Kingdom may be more deadly, UK Prime Minister Boris Johnson warned based on early evidence.
The data comes from mathematicians comparing death rates in people infected with either the new or the old versions of the virus.
The new more infectious variant has already spread widely across the UK.
Mr Johnson told a Downing Street briefing: “In addition to spreading more quickly, it also now appears that there is some evidence that the new variant – the variant that was first identified in London and the south east – may be associated with a higher degree of mortality.
“It’s largely the impact of this new variant that means the NHS is under such intense pressure.”
Evidence assessed by scientists concluded there was a “realistic possibility” that the virus had become more deadly, but this is far from certain.
Previous work suggests the new variant spreads between 30% and 70% faster than others, and there are hints it is about 30% more deadly.
The new variant was first detected in Kent in September. It is now the most common form of the virus in England and Northern Ireland, and has spread to more than 50 other countries.
The Pfizer and Oxford-AstraZeneca vaccine are both expected to work against the variant that emerged in the UK.