The announcement that the coronavirus strain sweeping Britain could be more deadly as well as more transmissible has raised fresh concerns about the variant that has spread to dozens of countries.
British experts initially indicated that the latest strain circulating in the United Kingdom — one of many that have emerged globally in recent months — is between 50% and 70% more transmissible.
The government said on Friday, however, that the new version could also be 30-40 per cent more deadly, although it stressed that the evaluation relied on sparse data.
What has changed?
Two independent studies by the London School of Hygiene and Tropical Medicine and Imperial College London were presented to Britain’s New and Emerging Respiratory Virus Threats Advisory Group in mid-January (NERVTAG).
They related data from people who tested positive for the virus in the community—rather than in the hospital—to mortality data and found that the risk of death associated with the new strain increased by approximately 30%.
The groups used slightly different approaches, but both of them compared people with new variants to those with older variants, taking into account other factors such as age and location and monitoring for hospitals under pressure.
Higher deaths were also observed in other research by Exeter University and Public Health England and both came up with even higher estimates.
On the basis of these analyses, NERVTAG claimed that there was “a realistic possibility” that a new variant infection would be associated with an increased risk of death compared to previously circulating variants.
The alarm has already been caused by the rise in transmissibility associated with the variant, and the more people the virus infects, the more severe illnesses and the likelihood of death can occur.
“Unfortunately, it looks as if this virus might be both” more contagious and potentially more lethal, John Edmunds, professor at the Center for Mathematical Modeling of Infectious Diseases at LSHTM, said Monday in a press conference.
“So it’s really a serious turn for the worse, unfortunately,” he said.
How reliable are the findings?
Researchers said that the data were still unclear and said that the picture would become clearer in the next few weeks.
Edmunds said that the results were “statistically significant”
But he said that although the studies used information from those examined in the group, most of the people who died of Covid-19 went straight to the hospital and were tested there.
Researchers don’t have hospital records yet.
NERVTAG suggested that this lag in data may be the reason why the studies did not find proof of a rise in hospitalizations for people with a new variant, which seems to be at odds with the results of increased disease severity.
It also stated that the mortality data used in the analysis only cover 8 per cent of the total deaths during the study period and stated that the findings “may therefore not be representative of the total population”
Why more deadly?
Researchers assume that it may be the same set of mutations that made it further infectious—though more research is required for all stress.
One mutation, in particular, enhances the ability of the virus to cling more closely to human cells and NERVTAG head Peter Horby, an emerging professor of infectious disease at Oxford University, said evidence indicates that this may make it easier to become infected.
“If it’s then able to spread between cells much quicker within the lungs, that may increase the rate of disease and the rate of inflammation, which may then progress quicker than your body can respond to, so it could explain both characteristics of the virus,” he said.
Bjorn Meyer, a virologist at the Institut Pasteur in France, told AFP that the problem could be viral loads.
“The virus might not have evolved to be more deadly as such, but it might have evolved to grow more or better, which could cause more damage in a patient overall,” he said.
Does this affect treatments?
Horby, who also led the Rehabilitation Trial—which identified steroid dexamethasone as successful for critically ill hospital patients—said there was “no evidence” that therapy would work less well.
Anti-inflammatory drugs such as dexamethasone “should work equally as well because it’s not related to the virus, it is related to the host response” he said.
Horby said that the overall change in therapies and treatments—including things like improved hospital respiratory support strategies—has lowered case fatality rates since the first wave and could even “offset any difference with this new variant”
As far as vaccinations are concerned, a preliminary analysis from the UK and the Netherlands this month showed that the version could not escape the protective effect of current vaccines.
Pfizer/BioNTech and Moderna have published early studies suggesting that their vaccines would still be successful against the strain.