The British SARS-CoV-2 Variant of Concern, B.1.1.7, Reveals Its Lethality

Several emerging SARS-CoV-2 variants of concern (VOCs) appear to have heightened infectivity and ability to evade natural or vaccine-derived immunity. Among the most prevalent of these is the B.1.1.7 VOC, first isolated in England in October 2020. This variant has spread to Europe, the U.S., and elsewhere, often superseding the wildtype virus. While B.1.1.7's increased infectivity soon became evident, whether this VOC also causes more-severe disease has been less clear. Two recent publications elucidate this issue.

A cohort study enrolled almost 55,000 individuals infected in the U.K. with the B.1.1.7 VOC and 55,000 infected with wildtype virus from October 2020 through January 2021; participants were matched by age, date of specimen collection, sex, ethnicity, and geographic location. Among all participants, 367 (0.3%) died within 28 days after testing positive for SARS-CoV-2: 141 in the wildtype arm and 227 in the B.1.1.7 VOC arm (hazard ratio, 1.6; P<0.001). Death rates in the two arms diverged only after 14 days, after which the hazard ratio was 2.4. Individuals in the B.1.1.7 VOC arm also had higher viral loads.

The second study included >1,146,000 patients in England identified by laboratory data, of whom about 5000 died from COVID-19. Among these, 58.8% were infected with the B.1.1.7 VOC and their adjusted mortality risk was estimated to be 61% elevated.