The announcement that the coronavirus strain that sweeps the UK could be both more deadly and more transmissible has sparked new concerns about the variant, which has spread to dozens of countries.
Initially, British experts said their evidence suggests that the new strain circulating in the UK – one of several that has surfaced internationally in recent months – was between 50 and 70 percent more communicable.
However, on Friday the government said the new variant could also be 30 to 40 percent more lethal, despite stressing that the assessment was based on sparse data.
What has changed?
In mid-January, the UK Advisory Group on New and Emerging Respiratory Virus Threats (NERVTAG) were presented with two separate studies from the London School of Hygiene and Tropical Medicine and Imperial College London.
They linked data from people who tested positive for the virus in the community rather than in the hospital with death data and found an increase in the risk of death associated with the new strain by around 30 percent.
The groups used slightly different methods, but both agreed people with the new variant with those with the older variants, taking into account other variables such as age and location, and control of hospitals under pressure.
Other studies from Exeter University and Public Health England also found higher deaths, and both found even higher numbers.
Based on these analyzes, NERVTAG stated that “there is a realistic possibility” that an infection with the new variant is associated with an increased risk of death compared to previously circulating variants.
The increase in communicability associated with the variant has already triggered an alarm, because the more people the virus infects, the more people suffer serious illnesses and the risk of death.
“Unfortunately, it looks like this virus could be both more contagious and potentially deadly,” said John Edmunds, a professor at the LSHTM Center for Mathematical Modeling of Infectious Diseases, in a press conference Monday
“So it’s really a serious turn for the worse,” he said.
How reliable are the results?
The researchers said there were still uncertainties in the data and the picture would become clearer over the next few weeks.
Edmunds said the results were “statistically significant”.
But he said while the studies used information from those who were tested in the community, most people who die from Covid-19 go straight to the hospital and get tested there.
Researchers don’t yet have this hospital information.
NERVTAG said this data lag could be the reason the studies found no evidence of an increase in hospital admissions for people with the new variant, which seems to contradict the results of increased disease severity.
It also states that the mortality data used in the study only covers eight percent of the total deaths during the study period and that the results “may therefore not be representative of the general population”.
Why more deadly?
The researchers believe it could be the same mutations that made it more contagious – though all strains require more study.
One mutation in particular increases the virus’ ability to bind more strongly to human cells, and NERVTAG boss Peter Horby, an aspiring professor of infectious diseases at Oxford University, said it suggests it might make the infection easier.
“If it can then spread much faster between cells in the lungs, it can increase the rate of disease and inflammation, which can then progress faster than your body can respond, so both properties of the virus can be explained.” ” he said.
Björn Meyer, a virologist at the French Pasteur Institute, told AFP that the problem could be viral load.
“The virus may not have turned out to be more deadly, but it may have turned out more or better which could do more harm to a patient overall,” he said.
Does this affect treatments?
Horby, who also leads the recovery study that identified the steroid dexamethasone as effective for critically ill hospital patients, said there was “no evidence” that treatments would work less well.
Anti-inflammatory agents like dexamethasone “should work equally as it is not related to the virus but to the host’s response,” he said.
According to Horby, general improvements in therapies and treatments – including better strategies for hospital airway support – have lowered the death rate since the first wave and might even “make up for any difference with this new variant.”
A preliminary study from the UK and the Netherlands this month found that the variant cannot escape the protective effects of current vaccines.
Pfizer / BioNTech and Moderna have also released early research suggesting their vaccines continue to be effective against the strain.
Don’t viruses weaken when they spread?
Scientists have tried to challenge the belief that as the virus evolves to become more contagious, it becomes less virulent.
The virus that causes Covid-19 is already “very good at transmitting,” said Emma Hocroft, epidemiologist at the University of Bern.
“So I don’t think we can assume that it should be less severe. I don’t want to downplay that it is severe for a lot of people, but for the majority of people it’s not severe,” she told AFP.
She said the ability to transmit before it kills is “a really low bar,” citing diseases like measles and HIV, which have remained dangerous.
Graham Medley, professor of infectious disease modeling at LSHTM, told the news conference on Monday that despite the uncertainties in the new studies on the new variant in the UK, they should dispel the idea that it is becoming less virulent.
“It is certainly not the case that this is a more harmless virus,” he said.
(Except for the headline, this story was not edited by GossipMantri staff and published from a syndicated feed.)