Is the Mutated U.K. Coronavirus Strain Deadlier?
Data suggesting it causes worse symptoms is preliminary. But concern is justified.
According to preliminary data, the mutated, more contagious variant of the coronavirus that originated in the U.K. might also be more virulent, meaning it would cause worse symptoms and potentially lead to more deaths on a per-case basis than the original strain of the virus.
But the limited data, based on only a few weeks of studying the new variant, is not yet as convincing as some headlines have suggested, several experts say.
Multiple emerging mutated coronavirus variants have generated well-founded scientific concern due to their increased contagiousness, which causes higher rates of infections, thus leading to more deaths — even if the variant isn’t inherently more deadly for each infected person. But now, multiple small studies indicate that people infected with the U.K. variant, named B.1.1.7, might be some 30% more likely to die than if they’d been infected by the preexisting strain.
A summary of the research was published by the U.K. government’s New and Emerging Respiratory Virus Threats Advisory Group (NERVTAG) last week. However, the studies in the analysis involved very small sample sizes and do not warrant firm conclusions yet, scientists say, though they agree that considerable concern, and ongoing study, is justified.
“The results of the NERVTAG analysis are concerning, although preliminary,” says Deepti Gurdasani, MD, an epidemiologist at Queen Mary University of London.
“We need to treat results with caution, as the analysis only included 8% of all deaths, given data for the variant was only available on a subset of samples,” Gurdasani tells me in an email. “We also need to consider the possibility that B.1.1.7, due to its increased transmissibility, may be infecting different groups of people that may be at greater risk of death with infection from any virus type. While the methods adjust for many of these factors, we can’t rule out this possibility at the moment.”