SARS-CoV-2 Variant B.1.1.7 Associated With a Significantly Higher Mortality Rate

March 11, 2021

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variant of concern 202012/01 (VOC 202012/01), from lineage B.1.1.7, is between 30% and 100% more deadly than previous strains, according to a study published the British Medical Journal.

Leon Danon, MD, University of Bristol, Bristol, United Kingdom, and colleagues compared death rates among people infected with the new variant and those infected with other strains. Results showed that variant B.1.1.7, also known as the UK variant, led to 227 deaths in a sample of 54,906 patients compared with 141 deaths among 54,906 closely matched patients who had the previous strains.

Participants were matched for age, sex, ethnicity, index of multiple deprivation, lower tier local authority region, and sample date of positive specimens, and differed only by detectability of the spike protein gene using the TaqPath assay.

“We focussed our analysis on cases that occurred between November 2020 and January 2021, when both the old variants and the new variant were present in the United Kingdom,” said Dr. Danon. “This meant we were able to maximise the number of ‘matches’ and reduce the impact of other biases. Subsequent analyses have confirmed our results.”

“In the community, death from COVID-19 is still a rare event, but the B.1.1.7 variant raises the risk,” added lead author Robert Challen, MD, University of Exeter, Exeter, United Kingdom. “Coupled with its ability to spread rapidly this makes B.1.1.7 a threat that should be taken seriously.”

The mortality hazard ratio associated with infection with B.1.1.7 compared with infection with previously circulating variants was 1.64 (95% confidence interval, 1.32 to 2.04) in patients who tested positive for SARS-CoV-2 in the community. In this comparatively low-risk group, this represents an increase in deaths from 2.5 to 4.1 per 1,000 detected cases.

“The probability that the risk of mortality is increased by infection with VOC-202012/01 is high,” the authors wrote. “If this finding is generalisable to other populations, infection with VOC-202012/01 has the potential to cause substantial additional mortality compared with previously circulating variants.”

“SARS-CoV-2 appears able to mutate quickly, and there is a real concern that other variants will arise with resistance to rapidly rolled out vaccines,” said Dr. Danon. “Monitoring for new variants as they arise, measuring their characteristics and acting appropriately needs to be a key part of the public health response in the future.”

Reference: https://www.bmj.com/content/372/bmj.n579

SOURCE: University of Exeter