Variant B.1.1.7 more transmissible but does not increase disease severity, two new studies suggest

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Covid-19 re-infections rare, but more common in people 65 and over, study finds



The results contradict separate research that previously suggested the variant may be linked to a higher risk of dying from Covid-19.

One of the studies, published Monday in The Lancet Infectious Diseases, found no evidence in a sample of hospital patients that variant B.1.1.7 is associated with severe Covid-19. However, the variant was associated with an increased viral load, confirming the 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 symptoms of Covid-19 that people said they experienced.

The Lancet Infectious Disease Study included data on 496 people admitted to London hospitals and tested positive for coronavirus infection.
“Our data, in the context and limitations of a real-world study, provide initial assurance that the severity in hospitalized patients with B.1.1.7 is not significantly different from the severity in those without do not, and this study provides a model to answer the same. question again as we enter an era of emerging variants, ”the UK-based researchers wrote in the study.

Nose and throat swabs were taken from patients between November 9 and December 20. Of these samples, 341 underwent genome sequencing. Sequence data showed that 198 of the patients, or 58%, had infections caused by the B.1.1.7 variant while the rest were caused by other strains of the coronavirus.

Researchers found no difference in the outcome of severe disease or death between the variant and the other lines.

For example, data showed that 36% of study patients with variant B.1.1.7 infection experienced severe illness or death, compared with 38% of those with non-B.1.1.7 infections. . Regarding death in particular, 16% of people with B.1.1.7 variant died within 28 days, compared to 17% of those with non-B.1.1.7 infections, the researchers found.

But researchers have identified an increased viral load in B.1.1.7 patients.

Overall, “patients with B.1.1.7 were younger and had fewer comorbidities than those with non-B.1.1.7 infection, possibly representing a generalized and potential increase in transmission of this variant in the community or differences in the likelihood of hospitalization, which we were unable to explore in this hospital cohort, ”the researchers wrote.

“Finding B.1.1.7 more frequently in younger individuals than in older people gives a subtle suspicion of more severe disease if patients with B.1.1.7 are hospitalized more often than patients with other lines, although the difference in disease severity was B.1.1 .7 was not found in this hospitalized cohort in the main analysis. “

“This study adds to the consensus that B.1.1.7 increased transmissibility”

The Lancet Public Health study included data on 36,920 people who reported testing positive for Covid-19 and recorded their symptoms in the COVID Symptom Study app between September 28 and December 27.

The app – designed by doctors and scientists at King’s College London, the Guys and St Thomas’ Hospitals and Zoe Global Limited, a healthcare technology company – helps track the spread of Covid-19 and the range symptoms experienced.

The study authors, based in the UK and US, analyzed data reported in the app as well as Covid-19 surveillance data for the UK.

The analysis showed that the prevalence of the B.1.1.7 variant in some regions and over time was not associated with the changes in symptoms of Covid-19 reported in the application or with the duration of symptoms.

“The proportion of users with asymptomatic disease did not change significantly as the B.1.1.7 variant increased in prevalence, consistent with other studies on the subject,” the researchers wrote in study. “We also found no change in hospital admissions; however, other reports have shown that variant B.1.1.7 increases hospital admission rates. “

Covid-19 re-infections rare, but more common in people 65 and over, study finds

Researchers found the rate of coronavirus re-infections to be low – with 0.7% of app users reporting a positive Covid-19 test again testing positive after 90 days – and there was no evidence increased reinfection rates associated with the B.1.1 .7 variant.

Researchers did not have data on the risk of dying from Covid-19 and most users of the app are only tested when they show symptoms, so there were relatively few asymptomatic infections in the data.

Still, the researchers found a “multiplicative increase” in the reproduction number of the B.1.1.7 variant, suggesting that it can spread more easily.

“This study adds to the consensus that B.1.1.7 increased transmissibility, which largely contributed to the sharp increase in cases in the UK during the study period and beyond, as well as ‘in the third wave underway in European countries with growing burdens of B.1.1.7 cases, ”Britta Jewell, of Imperial College London, wrote in an editorial accompanying the new study in The Lancet Public Health. Jewell was not involved in the new study.

“Although B.1.1.7 may have similar symptomatology to other lineages, the emergence of new variants is inevitable as long as the transmission of SARS-CoV-2 continues on a large scale,” Jewell wrote. “In other regions, especially in low- and middle-income countries that may have to wait longer to control their epidemics through vaccination, methods of real-time surveillance of symptoms and characteristics of the disease. , similar to the COVID Symptom Study, could help identify potentially significant changes in symptomatology, transmissibility, mortality, or avoidance of the vaccine as early as possible. “

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