UK coronavirus variant dominant in Hungary associated with significantly higher mortality

A pivotal study, by epidemiologists from the Universities of Exeter and Bristol, has shown that the SARS-CoV-2 variant, B.1.1.7 (UK or Kent variant), is associated with a significantly higher mortality rate amongst adults diagnosed in the community compared to previously circulating strains. 

The Kent variant, first detected in the UK in September 2020, has been identified as being significantly quicker and easier to spread, and was behind the introduction of new lockdown rules across the UK from January. By now it has become dominant in Hungary too.

The sample was 54,906 matched pairs of participants who tested positive for SARS-CoV-2 in pillar 2 between 1 October 2020 and 29 January 2021, followed-up until 12 February 2021.

The study found that the new variant led to 227 deaths compared to 141 amongst the same number of closely matched patients who had the previous strains.

"Healthcare capacity planning and national and international control policies are all impacted by this finding, with increased mortality lending weight to the argument that further coordinated and stringent measures are justified to reduce deaths from SARS-CoV-2," the authors of the study said.

In the community, death from COVID-19 is still a rare event, but the B.1.1.7 variant raises the risk. Coupled with its ability to spread rapidly this makes B.1.1.7 a threat that should be taken seriously

, said Robert Challen, lead author of the study from the University of Exeter.

The increase in mortality is of particular relevance to countries facing a surge in B.1.1.7. Clinicians and public health officials should be aware that a higher mortality rate is likely, especially where vaccination rates are low.

— Rob (Challen) March 10, 2021

Other key conclusions

The variant of concern being more lethal is expected to be associated with changes in its phenotypic properties because of multiple genetic mutations, and the authors see no reason why this finding would be specific to the UK.

This development, borne out in epidemiological analyses, implies that the rate of patients with serious infection requiring hospital attention will increase.

The resulting number of deaths will scale linearly with the proportion of people infected with the new variant. Other analyses have indicated that the new variant is also associated with increased transmissibility, which would lead to a potentially exponential increase in the resulting number of deaths.

Clinicians at the front line should be aware that a higher mortality rate is likely even if quality of practice remains unchanged.

This has broader implications for any vaccination allocation policy designed to reduce mortality in the late middle age groups, typical of the community identified patients in this dataset.

The question remains whether excess mortality due to VOC-202012/1 will be observed in other population groups, particularly elderly people, care home residents, and those with other comorbidities who generally present directly to hospital as an emergency.

Moreover, the emergence of VOC-202012/1 and its mutations (including E484K), combined with other variants of concern, including those identified in Brazil and South Africa, 

highlights the capacity of SARS-CoV-2 to rapidly evolve new phenotypic variants, with mutants that evade vaccines being a real possibility.

The authors noted that their study has helped to characterise the clinical presentation and outcome of one new variant, but given sufficient amounts of informative data their findings can be generalisable to other variants.

Assessment of the clinical outcomes of multiple circulating phenotypic variants, however, requires scalable technology that is capable of identifying substantial numbers of patients infected with emerging variants (eg, broad PCR assay panels targeting variant foci) and robust collection of outcome data.

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