Covid: why is the Delta variant more contagious?

Published by Laurent P. · Published on 21 July 2021 at 09h03
Covid Delta variant spreads faster... Here is the conclusion made by the Chinese Center for Disease Control and Prevention in a study issued as pre-print mid-July, saying the incubation time is quicker, moving from 6 to 4 days. A variant already known as being more contagious and more resitant to antibodies, WHO said this past May 8th.

Covid Delta variant is spreading faster... This is what the Chinese Center for Disease Control and Prevention concluded in a pre-print study issued this past July 12 on MedXRiv, explaining thanks to tracking and isolating contact cases, scientists realized the variant has a shorter incubation period, four days instead of six for the classic strain, making it more transmissible.

What did this study consist in? Following 167 people contaminated, from the patient zero infected this past May 21 in China. Every day, PCR tests were performed in contact cases isolated and results from the observations were clear: quicker contamination, in four days instead of six for the classic Covid strain. Scientists also stated the viral load was - according to their observations - 1.260 times bigger than the classic coronavirus viral load.

"One probably is more contagious and earlier because the virus multiplies faster and the viral load in the nose is much higher", Marseille-Luminy INSERM immunology center searcher Sandrine Sarrazin explains to Le Parisien. She goes on: "it is vital to stop the spread and prevent the emergence of variants likely to become of concern".

This Saturday May 8, Chief Scientist of the World Health Organization (WHO), Soumya Swaminathan already warned states about the “Indian” B.1.617 variant saying this strain of the virus “has some mutations which increase transmission, and which also potentially could make (it) resistant to antibodies that are generated by vaccination or by natural infection”.

A variant WHO could list among the most dangerous strains of the virus because it is more contagious and more likely to able to get past vaccine protection and the death rate of patients infected. The scientist added that vaccination on its own will not be enough in India, “at that point it's very hard to suppress, because it's then involving tens of thousands of people and it's multiplying at a rate at which it's very difficult to stop. […] It's going to take many months if not years to get to the point of 70 to 80 percent coverage” of people immunized in India, Swaminathan goes on.

The Indian variant cannot be held accountable for the extreme surge in cases in the country, the WHO Chief Scientist says, thinking the country has “let down their guard down” too soon, allowing “huge social mixing and large gatherings” before controlling the epidemic. she continues: “those early signs were missed until it reached the point at which it was taking off vertically”.

There is only one solution to control the epidemic: instating health measures already tested such as lockdown or curfew, which India refuses to do. “The more the virus is replicating and spreading and transmitting, the more chances are that... mutations will develop and adapt”, Swaminathan warns. She continues: “Variants which accumulate a lot of mutations may ultimately become resistant to the current vaccines that we have”, and she concludes: “That's going to be a problem for the whole world”.

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