A comparative study through a mathematical model where death rates of the new UK strain of the virus with the old version of the virus were compared, has indicated increased mortality.
Early evidence suggests the variant of coronavirus that emerged in the UK may be more deadly, the UK Prime Minister Boris Johnson said.
However, there remains a lot of uncertainty around the numbers – and vaccines are still expected to work.
The new more infectious variant has already spread widely across the UK and has become the dominant strain.
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 southeast – 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.”. He also tweeted We have now learned that, in addition to spreading more quickly, the new variant of the virus may also be associated with a higher degree of mortality. It is therefore more important than ever that we all follow the rules and stay at home, protect the NHS and save lives.
Public Health England, Imperial College London, the London School of Hygiene and Tropical Medicine and the University of Exeter have each been trying to assess how deadly the new variant is.
Their evidence has been assessed by scientists on the New and Emerging Respiratory Virus Threats Advisory Group (Nervtag).
The group notes
- The variant of concern (VOC) B.1.1.7 (New Strain) appears to have substantially increased
transmissibility compared to other variants and has grown quickly to become the
the dominant variant in much of the UK.
- Initial assessment by PHE of disease severity through a matched case-control study reported no significant difference in the risk of hospitalization or death in people infected with confirmed B.1.1.7 (New Strain) infection versus infection with other variants.
- Several new analyses are however consistent in reporting increased disease severity in people infected with VOC B.1.1.7 compared to people infected with non-VOC virus variants.
- The group concluded there was a “realistic possibility” that the virus had become more deadly, but this is far from certain.
- It also states that The relative increase in CFR appears to be apparent across age groups.
Sir Patrick Vallance, the UK government’s chief scientific adviser told BBC, that the data so far is “not yet strong”.
He said: “I want to stress that there’s a lot of uncertainty around these numbers and we need more work to get a precise handle on it, but it obviously is a concern that this has an increase in mortality as well as an increase in transmissibility.”
Previous studies suggest the new variant spreads between 30% and 70% faster than others, and there are hints it is about 30% more deadly.
For example, with 1,000 60-year-olds infected with the old variant, 10 of them might be expected to die. But this rises to about 13 with the new variant.
This difference is found when looking at everyone testing positive for Covid, but analyzing only hospital data has found no increase in the death rate. Hospital care has improved over the course of the pandemic as doctors get better at treating the disease.
The study, however, hints at increased mortality across age groups. 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 including India.
Assessment about the effectiveness of vaccination for new coronavirus strain
The UK PM statement was based on a mathematical model to assess the severity of the disease, this study does not cater to understanding the effectiveness of vaccination on the new strains. However, there are multiple studies going around the globe to assess the impact on the current vaccination efforts.
The Pfizer and Oxford-AstraZeneca vaccine are both expected to work against the variant that emerged in the UK. However, Sir Patrick said there was more concern about two other variants that had emerged in South Africa and Brazil.
He said: “They have certain features which means they might be less susceptible to vaccines.
“They are definitely of more concern than the one in the UK at the moment and we need to keep looking at it and studying this very carefully.”
Prime minister Johnson said the government was prepared to take further action to protect the country’s borders to prevent new variants from entering.
“I really don’t rule it out, we may need to take further measures still,” he said.
Last week the UK government extended a travel ban to South America, Portugal, and many African countries amid concerns about new variants, while all international travelers must now test negative ahead of departure to the UK and go into quarantine on arrival.
Meanwhile, the study says, since the time lag from infection to hospitalization and death is relatively long, data will accrue in coming weeks, at which time the analyses will become more definitive.