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Two new studies suggest that the variant of the coronavirus B.1.1.7, which was first identified in the United Kingdom, is more communicable, but does not appear to affect the severity of the disease.
The findings collide with separate research that previously suggested the variant may be linked to an increased risk of dying from COVID-19.
One of the studies, published Monday in
The Lancet Infectious Diseases
, found no evidence in a sample of hospitalized patients that variant B.1.1.7 is associated with severe COVID-19.
However, the variant was associated with an increase in viral load, supporting growing evidence that it is more easily transmitted.
The other study, also published Monday in
The Lancet Public Health
, found no statistically significant association between variant B.1.1.7 and the types or duration of COVID-19 symptoms that people said they experienced.
'Patients with B.1.1.7 were younger and had fewer comorbidities'
The study of
The Lancet Infectious Diseases
included data on 496 people who were admitted to hospitals in London and had tested positive for
coronavirus infection.
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“Our data, within the context and limitations of a real-world study, provide an initial assurance that the severity in hospitalized patients with B.1.1.7 is not markedly different from the severity in those without it, and this study provides a model for answering the same question again as we move into an era of emerging variants, 'the UK-based researchers wrote in the study.
Nose and throat swab samples were collected from the patients between November 9 and December 20.
Among those samples, 341 underwent genome sequencing.
The sequence data showed that 198 of the patients, or 58%, had infections caused by the B.1.1.7 variant, while the others were caused by other strains of the coronavirus.
The researchers found no difference in the outcome of severe illness or death between the variant and other strains.
For example, the data showed that 36% of patients in the study with the B.1.1.7 infection variant experienced severe illness or death compared to 38% of those with non-B.1.1.7 infections.
When it came to death specifically, 16% of those with the B.1.1.7 variant infection died within 28 days compared to 17% of those with non-B.1.1.7 infections, the researchers found. .
But the researchers identified an increase in viral load among patients with B.1.1.7.
In general, «patients with B.1.1.7 were younger and had fewer comorbidities than those with non-B.1.1.7 infection, possibly representing the potential and generalized increase in transmission of this variant in the community or differences in the probability of hospital admission, which we were unable to explore in this hospital cohort, ”the researchers wrote.
'The finding of B.1.1.7 more frequently in younger individuals than in older people gives a subtle indication of more severe disease if patients with B.1.1.7 are hospitalized more frequently compared to patients with other strains, although the difference in disease severity with B. 1.1.7 was not found in this hospitalized cohort in the main analysis. '
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'This study adds to the consensus that B.1.1.7 has increased transmissibility'
The study of
The Lancet Public Health
included data from 36,920 people who reported to test positive covid-19 and recorded their symptoms in the study Symptom Covid application between 28 September and 27 December.
The app, designed by doctors and scientists from King's College London, Guys and St Thomas' Hospitals and Zoe Global Limited, a healthcare technology company, helps track the spread of Covid-19 and the range of symptoms experienced.
The study authors, based in the United Kingdom and the United States, analyzed data reported in the app alongside covid-19 surveillance data for the United Kingdom.
The analysis showed that the prevalence of the B.1.1.7 variant in certain regions and over time was not associated with changes in reported COVID-19 symptoms or duration of symptoms.
"The proportion of users with asymptomatic disease did not change significantly as variant B.1.1.7 increased in prevalence, consistent with other studies on the subject," the researchers wrote in the study.
“Nor did we find changes in hospitalizations;
however, other reports have shown that variant B.1.1.7 increases hospital admission rates. '
The researchers found the coronavirus reinfection rate to be low, with 0.7% of app users reporting a positive test for covid-19 testing positive again after 90 days, and there was no evidence of an increase. in the reinfection rates associated with variant B. 1.1.7.
The researchers had no data on the risk of dying from COVID-19 and most app users get tested only when they have symptoms, so there were relatively few asymptomatic infections in the data.
However, the researchers found a "multiplicative increase" in the breeding number of the B.1.1.7 variant, suggesting that it may spread more easily.
'This study adds to the consensus that B.1.1.7 has increased transmissibility, contributing in large part to the strong increase in cases in the UK over the study period and beyond, as well as third waves ongoing in European countries with increasing B.1.1.7 case loads, ”wrote Britta Jewell of Imperial College London in an accompanying editorial in
The Lancet Public Health
.
Jewell was not involved in the new study.
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"Although B.1.1.7 may have similar symptomatology to other variants, the emergence of new variants is inevitable as long as SARS-CoV-2 transmission continues on a large scale," Jewell wrote.
«In other regions, especially in low- and middle-income countries that may face longer waits to control their epidemics through vaccination, real-time monitoring methods of symptoms and disease characteristics, similar to the Symptom Study of Covid, could help identify potentially important changes in symptomatology, transmissibility, mortality, or vaccine avoidance as soon as possible. "
Covid-19