The announcement that the coronavirus strain that is sweeping Britain could be more deadly as well as more communicable has raised new concerns about the variant that has spread to dozens of countries.
British experts initially said that their evidence suggested that the new strain circulating in the UK – one of several that emerged internationally in recent months – was between 50% and 70% more transmissible.
On Friday, however, the government said the new variant could also be 30-40 percent more deadly, although it emphasized that the assessment was based on sparse data.
What has changed?
In mid-January, two separate studies from the London School of Hygiene and Tropical Medicine and Imperial College London were presented to the New and Emerging Respiratory Virus Threats Advisory Group (NERVTAG).
They linked data from people who tested positive for the virus in the community – rather than the hospital – with death data and found an increase of about 30% in the risk of death associated with the new strain.
The groups used slightly different methods, but both combined people with the new variant with those with the older variants, taking into account other variables such as age and location and control for hospitals under pressure.
Other studies by Exeter University and Public Health England also found higher deaths and both had even higher numbers.
Based on these analyzes, NERVTAG said that there was “a realistic possibility” that infection with the new variant was associated with an increased risk of death compared to previously circulating variants.
The increase in transmissibility associated with the variant was already causing alarm, because the more people the virus infects, the more people will suffer serious diseases and there will be a risk of death.
“Unfortunately, it looks like this virus could be” more infectious and potentially more deadly, “said John Edmunds, a professor at LSHTM’s Center for Mathematical Modeling of Infectious Diseases at a news conference on Monday.
“So, unfortunately, it’s a serious turn for the worse,” he said.
How reliable are the findings?
The researchers said there are still uncertainties in the data and that the picture will become clearer in the coming weeks.
Edmunds said the findings were “statistically significant”.
But he said that while the studies used information from those tested in the community, most people who die of COVID-19 go straight to the hospital and are tested there.
The researchers do not yet have this information from the hospital.
NERVTAG said that this delay in the data may be the reason that the studies did not find evidence of an increase in hospitalizations of people with the new variant, which appears to be at odds with the findings of increased severity of the disease.
He also said that the mortality data used in the survey covered only 8 percent of total deaths during the study period and said that the results “may therefore not be representative of the total population”.
Why more deadly?
The researchers think it may be the same set of mutations that made it more infectious – although all the stress is in need of further study.
One particular mutation increases the virus’s ability to cling more tightly to human cells and the head of NERVTAG, Peter Horby, a professor of emerging infectious diseases at Oxford University, said the evidence suggests it means it can make it easier be infected.
“If it is able to spread between cells much faster inside the lungs, it can increase the rate of disease and the rate of inflammation, which can progress more quickly than your body can respond, so that could explain the two characteristics of the virus, “he said.
Bjorn Meyer, a virologist at the Institut Pasteur in France, told AFP that the problem could be viral load.
“The virus may not have evolved to be more deadly as such, but it may have evolved to grow more or better, which could cause more harm to the patient in general,” he said.
Does this affect the treatments?
Horby, who also leads the Recovery study – which identified the steroid dexamethasone as effective for critically ill hospital patients – said “there is no evidence” that treatments work less well.
Anti-inflammatories like dexamethasone “should work just as well because they are not related to the virus, they are related to the host’s response,” he said.
Horby said that overall improvements in therapies and treatments – including things like better strategies for hospital respiratory support – have reduced lethality rates since the first wave and may even “make up for any difference with this new variant”.
As for vaccines, a preliminary study this month from Britain and the Netherlands found that the variant would not be able to escape the protective effect of current vaccines.
Pfizer / BioNTech and Moderna also released initial research suggesting their vaccines would still be effective against the strain.
Don’t viruses weaken as they spread?
Scientists have tried to challenge the belief that the virus will become less virulent as it evolves to become more infectious.
The virus that causes COVID-19 is “already very good at its transmission work,” said Emma Hocroft, an epidemiologist at the University of Bern.
“So I don’t think we can make that assumption that he wants to be less serious. I don’t want to underestimate that it is serious for many people, but for most people, it is not serious,” she said AFP.
She said the ability to transmit before killing is “a very low standard”, citing diseases like measles and HIV, which remain dangerous.
Graham Medley, professor of infectious disease modeling at LSHTM, told the press on Monday that, despite the uncertainties in new studies on the new variant in the UK, they should dispel the idea that it would become less virulent.
“It is certainly not the case that this is a more benign virus,” he said.
© Agence France-Presse