Risk of Death from UK Variant Higher than Other COVID-19 Infections
Investigators in the United Kingdom modeled the comparative risk of death from COVID-19 and the B.1.1.7 variant.
The risk of death from COVID-19 variant found in Britain is higher than from the original variant, according to a paper published in Eurosurveillance.
Investigators from the United Kingdom studied the risk of death after a confirmed coronavirus case and compared the risk between a non-variant infection and the B.1.1.7 variant, which was first identified in Kent, United Kingdom. The investigators wrote that this variant is now the dominant UK strain and it is increasing in prevalence across Europe. The study authors wrote that their analysis also included factors about demographics and comorbidities.
To estimate the risk of death, the investigators used the OpenSAFELY electronic health records system, which incorporates 40 percent of England’s population who is registered with a general practitioner, plus COVID-19 testing data, and vaccination and mortality records. Those who tested positive for COVID-19 between Nov. 16, 2020 and Jan. 11, 2021 were followed until death or Feb. 5, 2021. If patients had been vaccinated against COVID-19, they were excluded.
The investigators identified 91,775 patients with the B.1.1.7 variant and 93,011 patients that had coronavirus, but not that variant. There were 867 all-cause deaths before the end of the follow-up period, the study authors reported, including 419 from the variant group and 448 from the non-variant group.
The variant and non-variant groups were similar demographically, the study authors said, though the variant group was younger and had a lower proportion of older cases (for example, aged 80 years or older: 0.9 percent in the variant group vs. 1.6 percent in the non-variant group). Non-variant cases were observed more frequently in the first 4 weeks of observation, while variant cases predominated thereafter, the study authors wrote. That meant that the median follow-up time was shorter among variant group patients compared to non-variant group patients.
Infection with the coronavirus variant was “consistently associated with an increased hazard of death,” the study authors explained. The hazards were two-thirds higher in the variant group compared with the non-variant group after accounting for demographics and comorbidities, they found. This increased risk was consistent across all subgroup analyses including epidemiological week, age group, categorical number of comorbidities, ethnicity, and index of multiple deprivation quartile, the study authors added.
Variant group patients had a consistently higher absolute risk of dying by 28 days after a positive test compared to non-variant group patients when analyzed by age, sex, and presence of comorbidities, the study authors observed. If a person with the variant was aged less than 65 years and had no comorbidities, their risk of death was low, the study authors noted. For patients under 65 years, they also found that the risk of dying was higher for male vs. female patients. Patients with the variant with the highest risk of death within 28 were those aged 85 years or older with 2 or more comorbidities, the study authors said.
“For every 3 deaths in a population with the previously circulating virus we would expect 5 deaths in a similar population with [the variant],” the study authors wrote, adding that their findings match the relative mortality observed in other studies. However, they also noted that their study was the first to include detailed information about the effects of the presence of comorbidities on the risk of death from the variant.
“Crucially, emerging data suggest that the currently approved vaccines for SARS-CoV-2 are effective against the B.1.1.7 [variant],” the study authors concluded. “This study highlights the importance of robust national vaccination programs and infection control measures to contain the SARS-CoV-2 pandemic. Unmitigated spread of the B.1.1.7 VOC has the potential to be both faster and more deadly than the pandemic to date.”