92% in France, what symptoms?

NEW VARIANT. This subvariant of Omicron is majority in France. It represents 92% of positive covid tests. The monoclonal antibodies Ronapreve and Evusheld could be used in preventive treatments against BA.2 What are your symptoms? How dangerous is it? Is it possible to get infected again?

[Mis à jour le 11 avril 2022 à 15h40] B.A.2 is a Omicron subvariantitself a variant of SARS-CoV-2. BA.2 and responsible for the recent resumption of the epidemic. The symptom of BA.2 infection are the same as those caused by Omicron: fatigue, cough, fever… The Sublineage BA.2 is majority in Francerepresenting 92% of positive covid tests analyzed by Public Health France according epidemiological point of April 7. He is more contagious than the BA1 Omicron sub-variant that first appeared in France. But it doesn’t show up no more danger. French researchers fromPastoral Institute They have studied the efficacy of Ronapreve monoclonal antibodies® (combination of two antibodies developed by Roche/Regeneron) Y evusheld® (combination of two antibodies developed by AstraZeneca) against the Omicron variant (BA.1 and BA.2) of the coronavirus. By last, BA.1, and to a lesser extent BA.2, is less sensitive to Evusheld® and Ronapreve® what Delta. The antibodies and corresponding sera have little or no activity against BA.1, but they are more active against BA.2. Compared to Delta, the neutralizing activity is more severely decreased against BA.1: 344 times more antibodies are needed to neutralize BA.1 and 9 more times to neutralize BA.2explains Timothée Bruel, first author of the study published on March 23. What is this new mutation? of covid-19? It’s her more contagious, more dangerous, What omicron? the vaccine effective against this new variant? which are the symptoms of BA.2 ? To update.

Definition: what is the new variant BA.2?

The BA.2 is a Omicron subvariant. It is a “little cousin” of the Omicron variant“explained Jean-François Delfraissy, president of the Covid Scientific Council, at the microphone of France information in January. Named BA.2, it is a sublineage of Omicron like BA.1 (which was circulating until now) or BA.3. “The the genetic sequence of the BA.2 subvariant differs from that of BA.1 and shows marked amino acid differences in the Spike protein and other proteins” indicated theWHO in February 2022.”The most recent data seem to confirm that BA.1 and BA.2 show similar severity and evasion of the immune response and therefore BA.2 is not considered a distinct variant but is included in the Omicron VOC” . specifies Public Health France. However BA.2 “is he most contagious variant from virus SARS-CoV-2 we have seen so far“, warned Maria Van Kerkhove of the WHO, on March 19 at a press conference.

What is the rate for the BA.2 variant in France?

The BA.2 Omicron variant is now more present than the BA.1 variant, mainly circulating since the end of 2021 in France. As of April 7, according to Public Health France, BA.2 represents 92% Omicron sequences analyzed during the week of March 21-27. “The progression of BA.2 to the detriment of BA.1 is observed in the entire metropolitan area, but at different levels depending on the region. In DROMs, BA.2 also appears to be increasing, but the data needs to be consolidated.“adds the organization.

What are the symptoms of the BA.2 variant?

At the moment, there are no specific symptoms listed in cases of the BA.2 subvariants. On the other hand for the Omicron variant”Epidemiological investigations indicate a specific clinical presentation with more upper respiratory symptoms Y less loss of taste and smell, as well as less severity (up to 80% lower risk of hospitalization and admission to intensive care)“reported Public Health France 26 of January. Symptoms of the BA.2 variant (like Omicron in general) can be:

  • tiredness;
  • Cough ;
  • Fever ;
  • Headache
  • muscle aches or body aches;
  • Throat pain ;
  • Runny nose ;
  • nausea and vomiting
  • Unpleasant breathing (more rarely)
  • Loss of taste and smell (more rarely)

Is the BA.2 variant more contagious than Omicron?

BA.2 is more communicable than BA.1 (39% secondary attack rate for BA.2 vs. 29% for BA.1). A study also estimates that the generation interval (time between two cases) of BA.2 is 15% lower than that of BA.1. These differences in transmissibility explain the rprogressive placement of BA.1 by BA.2 globally observed” emphasizes French Public Health on March 25. BA.2 “is he most contagious variant of the SARS-CoV-2 virus that we have seen so farsaid Maria Van Kerkhove, a WHO epidemiologist, on March 19.

Proportion of BA.2 cases over total sequences deposited in GISAID, by country as of February 21, 2022 © Public Health France

What are the risks of reinfection with BA2?

The frequency of possible SARS-CoV-2 reinfections has increased markedly since the introduction and distribution in France of the Omicron variant, in early December 2021, notes Public Health France.

“The upward resumption of SARS-CoV-2 circulation observed for several weeks in France and therise of the Omicron BA.2 sublineage, majority from week 09-2022 are two factors that may play a role in the current trend of increasing numbers of reinfections” agency confirms. Several recent studies have highlighted the possibility of BA.2 reinfection after BA.1 infection, even in a very short period of time (less than 60 days). “However, they do agree that these are probably rare events.”

Is the BA.2 variant more dangerous than Omicron?

Omicron’s BA2 subvariant does not “cause a more severe form” of Covid than BA1, according to Maria Van Kerkhove, epidemiologist in charge of the WHO’s emerging diseases unit, on March 19. However, with a large number of cases, you will see an increase in hospitalizations and this will turn into an increase in deaths.…”. He stated that there is no not “difference in terms of severity between BA1 and BA2“.

In France, screening strategy can detect all Omicron without distinction, if they are BA.1 or BA.2 and therefore reactively know the level of circulation of the variant” noted Public Health France. In a second time, a sequence allows differentiation between subvariants BA.1 and BA.2 Detection allows to reactively follow the Omicrons as a whole and sequencing allows a finer analysis of the different sublineages. [BA.1 ou BA.2]“.

Are vaccines against the BA.2 variant effective?

“The efficacy of the vaccine against symptomatic disease caused by BA.1 and BA.2 is similar: after two doses the efficacy is 10% for BA.1 and 18% for BA.2, after three doses the efficacy against symptomatic disease is 69% for BA.1 and 74% for BA.2 Efficacy drops to almost 50% two and a half months after the 3rd dose for BA.1 and BA.2“according to the study of the British health agency published on February 25”.This suggests that vaccination is at least as effective in preventing acquisition of BA.2 and may be more effective in preventing transmission of BA.2 than BA.1“, remarked the WHO.”Lthe efficacy of the vaccine is maintained against Omicron after the administration of a booster dose, especially against severe forms“Public Health France confirmed on January 26.

What treatments to prevent infection by the BA.2 variant?

various treatments for monoclonal antibodies are available to prevent Covid-19 infection. Researchers from the Institut Pasteur, the CNRS, the Vaccine Research Institute (VRI), in collaboration with the CHR d’Orléans, the AP-HP, KU Leuven (Catholic University of Leuven) and the Université Paris Cité studied theefficacy of two combinations of monoclonal antibodies Ronapreve therapies (combination of two antibodies developed by Roche/Regeneron) Where evusheld (combination of two antibodies developed by AstraZeneca) against the variant Omicron (BA.1 and BA.2) of the coronavirus. “We show that the antibodies and corresponding sera are little or not active against BA.1, but they are more active against BA.2. Compared to Delta, the neutralizing activity is more severely decreased against BA.1: 344 times more antibodies are needed to neutralize BA.1 and 9 more times to neutralize BA.2“, explains Timothée Bruel, first author of thestudy published on March 23 in Nature Medicine and researcher at the Virus and Immunity Unit of the Institut Pasteur (mixed research unit of the CNRS). Four Omicron infections were described among 29 antibody-treated patients (including one severe case). “This indicates that, in this case, treatment does not fully protect against infection or severe forms“explains Thierry Prazuck, co-senior author of the study and head of the infectious diseases department at CHR d’Orléans.

Sources:

– “Serum neutralization of SARS-CoV-2 Omicron BA.1 and BA.2 sublines in patients receiving monoclonal antibodies”, Nature Medicine, March 23, 2022

– “SARS-CoV-2 variants of concern and variants under investigation in England”, British Health Agency, 25 February 2022

– “Coronavirus: circulation of SARS-CoV-2 variants”, updated February 25, 2022, Public Health France

-“BA.2 is more transmissible than BA.1 but vaccinated people are less likely to become infected and transmit infection”, Jan. 31, Statens Serum Institut.

– COVID-19: epidemiological update of January 27, 2022, Public Health France

– “Risk analysis on emerging variants of SARS-CoV-2”, January 26, 2022, Public Health France.

– “Now an Omicron variant, BA.2, accounts for nearly half of all Danish Omicron cases” Jan 20, 2022, Statens Serum Institut.

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