Death rate 64% higher with B117 COVID variant, study finds
The 28-day risk of death for the B117 COVID-19 variant was 64% higher than for previously circulating strains in people older than 30 years, a UK study finds.
The study, led by University of Exeter researchers and published today in BMJ, involved community-based testing and death data from 54,906 matched pairs of participants who tested positive for COVID-19 from Oct 1, 2020, to Jan 29, 2021.
Of the 109,812 total participants, 367 (0.3%) died. Of the 54,906 participants infected with B117, 227 (0.4%) died, compared with 141 (0.3%) infected with other strains.
The hazard ratio (HR) for death by 28 days after diagnosis was 1.64 (95% confidence interval [CI], 1.32 to 2.04) for patients infected with the B117 variant, compared with previously circulating SARS-CoV-2 strains.
While the HR for death was not significantly higher in those infected with B117 up to 14 days after diagnosis, it rose to 2.40 (95% CI, 1.66 to 3.47) during days 15 to 28. Participants who died were older (mean age, 66.9 vs 46.3 years) than their peers, and more were men.
“In this comparatively low risk group, this represents an increase in deaths from 2.5 to 4.1 per 1,000 cases,” the authors wrote. “The increased hazard ratio between 1.32 and 2.04, higher than for other variants, translates to a 32% to 104% increased risk of death, with the most probable hazard ratio estimate of 1.64, or a 64% increased risk of death. The absolute risk of death in this group of community identified participants, however, remains relatively low.”
B117 was first identified in the United Kingdom in October 2020 and quickly became dominant, triggering a national lockdown and igniting concerns about possible increased transmission and disease severity.