The “Indian” variant will he derail the prudent strategy of British deconfinement? For several weeks, England has been concerned about the upsurge in new cases of Covid-19, and especially the growing presence of the B.1.617.2 variant, a variation of the strain discovered in India and which has spread throughout dozens of countries. While the number of cases was limited to a few thousand between the 12th and 19th, its presence in the United Kingdom has further increased in recent days. Last week nearly 7,000 cases were listed. Guest of the BBC, Professor Ravi Gupta, member of the advisory group on threats of new and emerging respiratory viruses (Nervtag), did not hesitate, Monday, to qualify its growth “exponential”.
“Of course the number of cases is relatively low at the moment, but all the waves start with a low number that circulate silently and then explode. What we see here shows all signs of an early wave,” he added. he. Until May 9, the dominant strain discovered in the new positive tests remained the variant B.1.117 (the “British”), but the trend has reversed to the point that “the Indian” is now in the majority.
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This B.1.617.2 variant is one of the three versions (B.1.617.1, B.1.617.2 and B.1.617.3), of the “Indian” variant. It is also the one that has experienced spectacular growth since the beginning of April until it is currently the very majority variant in India, recalls the French Scientific Council in its latest opinion. “It is therefore the B.1.617.2 variant which has become the largely majority variant in India, having dominated the British variant and the other so-called” Indian “variant subtypes in a context of very high viral circulation”, underlines the Council. According to figures from the British health agency, on May 16, it represented more than 58% of new contaminations sequenced in the country.
Up to 50% more transmissible
If this version of the virus was first detected in people returning from international trips, and in particular from India, cases of community contamination have accelerated in recent days. In some densely populated areas, where there are many multigenerational outbreaks, the first imported cases quickly blew up the circulation of the virus. Thus in the north-west of England, near Manchester, the city of Bolton has experienced a very strong increase in the number of cases, especially in young populations, and poorly vaccinated. “In Bolton, cases first increased in adolescents, in connection with homes in schools,” notes the Scientific Council. Clusters have also been discovered in London. In these regions, the authorities have dispatched military troops to speed up vaccination.
Why is he worrying? On the one hand, the B.1.617.2 variant seems to be more contagious, which explains in particular that it took precedence over the strain of Kent, that described as the British variant. If the data on its contagiousness still need to be consolidated, in its opinion the scientific council estimates that the B.1.617.2 variant could be up to 50% more transmissible than the British variant.
But that’s not all. In a study published on May 27 on the pre-publication site bioRxiv, researchers at the Institut Pasteur (Paris) showed that this virus would be less sensitive to neutralizing antibodies developed by Covid-19 patients convalescing or produced after vaccination. The researchers (the team of Delphine Planas and Olivier Schwartz) have notably shown that in people vaccinated with Pfizer’s product, the quantity of neutralizing antibodies produced during an infection with B.1.617.2 was 16 times lower compared to those neutralizing the British variant B.1.1.7 and 3 times lower than those neutralizing against the South African variant B.1.351.
Very low efficacy of single dose vaccination
The UK is clenching its teeth, because if a good part (almost 60%) of its population has received at least one dose of the vaccine, it is with AstraZeneca serum. However, as the Scientific Council noted in its opinion, “the first real-life data available in the United Kingdom suggest a vaccine efficacy preserved against all clinical forms of infection by B.1.617.2 after two doses Astra-Zeneca (60%) and Pfizer (88%), but not after a dose (33% for each vaccine) “. For the British, it is now a question of speeding up the vaccination campaign for the second dose.
The British government is being cautious about lifting the remaining restrictions, which was due to take place on June 21, and in recent days has refused to completely rule out the possibility of a continuation of certain measures such as maintaining teleworking. Prime Minister Boris Johnson had to concede that the goal of reopening could be changed, ensuring “wait for more data” to make a decision.
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Some European countries have already started to take action. Germany has decided to close its borders to travelers from the UK. In France it is necessary, since Monday, to justify a “compelling reason” to enter the territory from the United Kingdom, but also to have a negative PCR or antigen test of less than forty-eight hours, and s’ isolate seven days upon arrival.