Why scientists think UK variant could be more deadly
The announcement that the coronavirus strain sweeping Britain could possibly be more deadly along with more transmissible has raised fresh concerns about the variant which has spread to a large number of countries.
Initially British authorities said that their evidence suggested the brand new strain circulating in the UK -- one of the to have emerged internationally lately -- was between 50 percent and 70 percent more transmissible.
On Jan 22, however, the government said the brand new variant may be 30-40 percent more deadly, though it stressed the assessment relied on sparse data.
What has changed?
In mid-January, two separate tests by London School of Hygiene and Tropical Medicine and Imperial College London were presented to Britain's New and Emerging Respiratory Virus Threats Advisory Group (NERVTAG).
They linked data from people who tested positive for the virus locally -- instead of in hospital -- with death data and found a roughly thirty percent increase in the risk of death associated with the new strain.
The groups used slightly different methods, but both matched persons with the brand new variant to people that have the older variants, taking into account other variables like age and location and controlling for hospitals staying under pressure.
Other tests by Exeter University and Public Health England also found higher deaths and both developed even higher figures.
Based on these analyses, NERVTAG said there was "an authentic possibility" that an infection with the new variant is connected with an increased threat of death compared with previously circulating variants.
The upsurge in transmissibility associated to the variant was already causing alarm, because the more people the virus infects the more persons will suffer serious illness and the chance of death.
"Unfortunately, it appears as if this virus could possibly be both" more infectious and potentially more deadly, said John Edmunds, a professor found in LSHTM's Centre for the Mathematical Modelling of Infectious Diseases.
"So it's a really serious turn for the worse unfortunately," he said.
How reliable are the findings?
Researchers said there have been still uncertainties found in the data and said the picture would become clearer within the next few weeks.
Edmunds said the findings were "statistically significant".
But he said while the studies used information from those tested locally, many people who die of Covid-19 go right to hospital and are tested there.
Researchers do not yet have that hospital information.
NERVTAG said this lag in data could be why the studies didn't find evidence of a rise in hospitalisations of men and women with the new variant, which seems in odds with the findings of increased severity of disease.
In addition, it said the mortality data found in the research only covers eight percent of the total deaths during the study period and said the results "may therefore not be representative of the full total population".
Why more deadly?
Researchers think it could be the same set of mutations that features managed to get more infectious -- although all stress more study is needed.
One mutation specifically increases the virus' ability to latch about more strongly to human cells and NERVTAG head Peter Horby, an emerging infectious disease professor at Oxford University, said evidence suggests this implies it might make it simpler to become infected.
"If it's then in a position to spread between cells more speedily within the lungs, that may perhaps improve the rate of disease and the rate of inflammation, which might then progress quicker than the body can respond to, so that it could describe both characteristics of the virus," he said.
Bjorn Meyer, virologist in France's Institut Pasteur, told AFP that the issue could possibly be viral load.
"The virus might possibly not have evolved to become more deadly as such, nonetheless it may have evolved to grow more or better, that could cause more damage in an individual overall," he said.
Does indeed this affect treatments?
Horby, who also leads the Recovery trial -- which determined the steroid dexamethasone just as effective for severely ill hospital patients -- explained there is "no evidence" that treatments would work less well.
Anti-inflammatories such as dexamethasone "should work just as well because it isn't linked to the virus, it really is related to the host response", he said.
Horby said overall improvements in therapies and treatments -- including things like better approaches for hospital respiratory support -- have brought down case fatality rates since the first wave and may even "offset any kind of difference with this new variant".
As for the vaccines, an initial study this month from Britain and the Netherlands found the variant wouldn't normally manage to evade the protective aftereffect of current vaccines.
Pfizer/BioNTech and Moderna have also released early research suggesting their vaccines would still be effective against any risk of strain.
Don't viruses weaken because they spread?
Scientists experience sought to challenge the belief that the virus can be get less virulent since it evolves to be more infectious.
The virus that triggers Covid-19 is already "very proficient at its job of getting transmitted" said Emma Hocroft, an epidemiologist at the University of Bern.
"So I don't feel that we can make this assumption that it wants to get less severe. I don't prefer to downplay that it is severe for most people, but for many people, it's not severe," she told AFP.
She said the opportunity to transmit before it kills was "a really low bar", citing ailments like measles and HIV that contain remained as dangerous.
Graham Medley, a professor of Infectious Disease Modelling in the LSHTM, said that despite uncertainties found in the new studies on the brand new variant found in the UK, they should dispel the theory that it would become less virulent.
"It's definitely not the case that is a more benign virus," this individual said.
Source: japantoday.com
