Covid: UK variant not likely to cause more severe disease, two studies found

Published by Laurent P. · Published on 13 April 2021 at 10h53
According to two new studied released on Monday April 12 in The Lancet Infectious Diseases, the Covid UK variant is not likely to lead to more severe virus, but confirms it is more transmissible. The two studies go contrary to another publication issued on March 10, 2021, in the British Medical Journal, the UK variant is said to be 64% more deadly than classic Covid.

The Covid UK variant keeps on raising questions... According to two new studies released in The Lancet Infectious Diseases on Monday April 12, the UK strain of the virus does not to more severe and clinical cases than classic coronavirus, but has increased transmissibility.

What were the two studies about? The first one analyzed data of 341 patients hospitalized in London between November 9 and December 20, when this new variant started to grow big in the UK. In these 341 patients, 58% of them had been contaminated by this strain of the virus, while the remaining 42% had been infected by other variants. In the 58% that had caught the UK variant, 36% of them developed severe disease or died, against 38% in the group that had been contaminated by another strain. Data remain yet too light to come to such conclusion, the study only had a too little sample.

The second publication - issued in The Lancet Public Health - assessed data from a much larger group, including 37,000 users of a Smartphone application designed to report onset symptoms between September 28 and December 27, 2020. By taking the number of people who reported symptoms every week into account, the study concludes the UK strain reproduction rate was 1.35 time higher, but did not cause more clinical cases in severe disease.

These results go against the ones made out by a previsous study on the matter released this on March 10 in the  British Medical Journal, the UK variant is indeed more deadly than the classic form and leads to 64% more risk to die. The study confirms the preliminary data reported back to late January and shared by British Prime Minister Boris Johnson A stronger mortality that seems to particularly infect elderly men.

The probability that the risk of mortality is increased by infection”, researchers from the Exeter and Bristol universities carrying out the study explained. What was it about? Scientists relied on already existing data, including 110,000 Covid+ people between October 2020 and January 2021. Patients have then been followed up for 28 days.

Among these 110,000 people, half of them have been infected with the classic virus, the other with the variant in question. Scientists then compared mortality in both groups (141 deaths vs 227), taking into account some factors such as age, gender or ethnicity. This is how they noticed the UK variant was 64% more deadly.

This past January, the Prime Minister explained at a press briefing on 10 Downing Street why he was worried about the strain’s lethality: “It also now appears that there is some evidence that the new variant that was first identified in London … may be associated with a higher degree of mortality”. He relied on data shared by his scientific adviser Patrick Vallance who says the mortality rate with this new variant is roughly 13 to 14 in 1,000 namely a few points higher than the “standard” virus (10 for 1,000).

But Dr. Vallance yet intended to soften his sayings: “I want to stress that there is a lot of uncertainty around these numbers” adding that “it obviously is a concern that this has an increase in mortality as well as an increase in transmissibility”. In the meantime, this new mutation of the virus is spreading all over the world and is now found in about sixty countries.

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