The announcement that the coronavirus strain sweeping Britain could be more deadly and more transmissible has raised new concerns about the variant that has spread to dozens of countries.
Initially, British experts said their tests suggested that the new strain circulating in the UK – one of several that has appeared internationally in recent months – was transmissible between 50 and 70 per cent.
On Friday, however, the government said the new variant could also be 30-40 per cent more deadly, although it stressed that the assessment was based on scarce 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 Advisory Group on New and Emerging Respiratory Virus Threats (NERVTAG) in Britain.
They related data from people who tested positive for the virus in the community, rather than in the hospital, to mortality data and found a 30% increase in the risk of death associated with the new strain.
The groups used slightly different methods, but both matched people with the new variant with those of the older variants, taking into account other variables such as age and location, and controlling hospitals that were under pressure.
Other studies from the University of Exeter and Public Health England also found higher deaths and both gave even higher figures.
Based on these analyzes, NERVTAG said there was “a realistic possibility” that infection with the new variant was associated with a higher risk of death compared to previously circulating variants.
The increase in transmissibility associated with the variant was already causing alarm, because the more people become infected with the virus, the more people will suffer serious illness and risk of death.
“Unfortunately, this virus appears to be ‘more infectious and potentially more deadly,'” John Edmunds, a professor at LSHTM’s Center for Mathematical Modeling of Infectious Diseases, said Monday
“So it’s an unfortunate serious one,” he said.
How reliable are the results?
The researchers said there were still uncertainties in the data and said the picture would become clearer in the coming weeks.
Edmunds said the findings were “statistically significant.”
But he said that while the studies used community-proven information, most people who die of COVID-19 go straight to the hospital and get tested there.
Researchers do not yet have this hospital information.
NERVTAG said this lag in the data could be the reason why studies found no evidence of an increase in hospitalizations of people with the new variant, which appears to be at odds with the results of the increase in the severity of the disease.
He also said that the mortality data used in the research only cover 8% of the total deaths during the study period and that the results “may therefore not be representative of the total population”.
Why more deadly?
Researchers think it could be the same set of mutations that have made it more infectious, although more study is needed for all stress.
One mutation, in particular, increases the virus’s ability to adhere more strongly to human cells, and NERVTAG chief Peter Horby, an emerging professor of infectious diseases at Oxford University, said the tests suggest that this may make it easier to become infected.
“If you can then spread between cells much more quickly inside the lungs, this can increase the rate of disease and the rate of inflammation, which can progress faster than your body can respond to, so that could explain the two features 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 could have evolved to grow more or better, which could cause more harm to a patient in general,” he said.
Does this affect treatments?
Horby, who also leads the recovery trial, which identified the steroid dexamethasone as effective for severely hospitalized patients, said there is no “evidence” that the treatments work less well.
Anti-inflammatory drugs such as dexamethasone “should work equally well because they are not related to the virus, but are related to the host response,” he said.
Horby said overall improvements in therapies and treatments, including the best hospital respiratory support strategies, have reduced mortality rates from the first wave and may even “make up for any difference with this new variant.”
As for vaccines, a preliminary study conducted this month in Britain and the Netherlands found that the variant would not be able to evade the protective effect of current vaccines.
Pfizer / BioNTech and Moderna have also published initial research suggesting that their vaccines would still be effective against the strain.
Do viruses not weaken as they spread?
Scientists have tried to challenge the belief that the virus will become less virulent as it evolves and becomes 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 it wants to be less serious. I don’t want to downplay that it’s serious for a lot of people, but for most people it’s not serious,” he said. AFP.
He said the ability to transmit before killing was “a very low bar,” citing diseases such as measles and HIV that have been so dangerous.
Graham Medley, Professor of Infectious Disease Modeling at LSHTM, told Monday’s press conference that despite uncertainties from new studies on the new variant in the UK, they should dispel the idea that it would become less virulent.
“It’s not true that it’s a more benign virus,” he said.
© France-Presse Agency