The Covid BA.5 variant, a sub-lineage of Omicron, is gradually replacing BA.2 in France and now represents 41% of positive Covid tests. It is more transmissible and more eludes vaccine. It could lead to loss of taste and smell.
[Mise à jour le 24 juin 2022 à 10h52] The initial virus of the Covid-19 disease, Sars-Cov-2, mutated several times to the variant Omicron which began to arrive at the end of 2021 in France. Today in the majority, this variant has five sublineages of which the BA.5 which spreads rapidly in June in France and replaces BA.2. “During the Flash Week 23 survey (June 6-12), BA.2 accounted for 33% of interpretable sequences and BA.5 41% while in Flash Week 22, observed data showed 55% for BA.2 and 23% for BA.5” report Public Health France in its epidemiological update of June 23. “If we compare BA.4, BA.5 compared to BA.2 which caused a surge in March, BA.2 was already different from the Omicron variant of December-January because it was more transmissible . But he is no longer immune to the vaccine. Now, we have BA.4, BA.5 which propagate better than BA.2. That one, he escapes the vaccine a little better. And it shows the evolutionary capacity of the virus which is able to evade vaccines, at the same time as increasing its transmission. But we also know that the symptoms are not more severe“explained infectious disease specialist Anne-Claude Crémieux on June 22 on franceinfo.. Public Health France nevertheless stresses that “the probability of present anosmia [perte d’odorat] and ageusia [perte du goût]but also nausea, vomiting and diarrhea is higher for the cases of BA.4/BA.5 compared to those of BA.1″. What are these new variants Covid? Do they lead to symptoms different ? in France, dangers… Point.
What is the BA.5 variant?
BA.4 and BA.5 are sublineages of the Omicron variant of Covid-19. The BA.4 and BA.5 sublineages began to be identified in January and February 2022 in South Africa according to ECDC; early April according to Public Health France. They spread to Portugalleading to a new wave of Covid-19 in May that was particularly virulent for the over 80s.
What are the symptoms of the BA.5 variant?
According to Santé Publique France, the most frequent clinical signs in the event of infection with the BA.4 and BA.5 variants are fatigue, cough, fever and headache. Furthermore, “the probability of present anosmia [perte d’odorat] and ageusia [perte du goût]but also nausea, vomiting and diarrhea is higher for BA.4/BA.5″ cases says the health agency.
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How long do symptoms of the BA5 variant last?
The duration of clinical signs is on average 7 days for BA.4 and BA.5 cases versus 4 days for other Omicron cases.
What is the rate of the BA.5 variant in France?
“In France, we observe a gradual replacement of BA.2 by BA.5which represents 41% interpretable sequences of Flash Week 23 (compared to 24.2% for Flash Week 22). BA.4 detection is also increasing but at lower levels: 6% in week 23” noted Public Health France June 23.
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Is the BA.5 variant more contagious?
“The BA5 is more contagious than BA2. Considering the fact that it is more contagious, it escapes post-vaccination immunity a little better so we will probably continue to see this resurgence of new cases in the coming weeks“, explained Yves Buisson, president of the Covid cell of the Academy of Medicine on Europe on June 7. The sub-lineages of Omicron BA.4 and BA.5 replaced the BA.2 and led to a new epidemic wave in South Africa (5th wave). Same thing for the BA.5 exclusively au Portugal (without major epidemiological impact at this stage).
→ In South Africa : le BA.4 growth rate is +8% per day compared to BA2; +12% for BA.5.
→ Au Portugal : “Ain Portugal, BA.5 is today majority, with 69% in week 21.. BA.5 was associated with an epidemic recovery in the country, but the peak of this wave that started at the end of April now seems to have passed. If this is confirmed, the amplitude of the wave will have been much less than the previous one.“ indicates Public Health France on June 15.
Is the BA.5 variant more dangerous?
Data accumulated in several countries did not observe an increase in severity associated with BA.4 and BA.5. According to the latest ECDC epidemiological report reported by Santé Publique France on June 15, “There is currently no indication of any change in severity for cases infected with BA.4 or BA.5 compared to other Omicron sublines”. The rate
of hospitalization is not significantly higher for BA.4 and BA.5 compared to BA.1 and the majority of hospitalized cases present risk factors. “The median length of hospitalization (for BA4 or BA5 cases, editor’s note) is 5 days“adds the health organization.
What are the differences between the BA.5 variant and the BA.2 variant?
“BA.4, BA.5 spread better than BA.2. This one (BA5, editor’s note) escapes the vaccine a little better. And it shows the evolutionary capacity of the virus which is able to evade vaccines, at the same time as increasing its transmission. But we also know that symptoms are not more severe“said epidemiologist Anne-Claude Crémieux on June 22 on FranceInfo. “These two sub-lineages are quite similar to BA.2 but their Spike protein also has the mutations L452R/F486V and the R493Q reversion. BA.4 and BA.5 soon replaced BA.2 in South Africa. BA.4 and BA.5“reported Public Health France on May 18. The mutation L452R, which was also found on the Delta variant, is on the rise again in June in positive Covid tests. L’Median age des cas investigated in France est de 47 years old, higher than that of BA.1 infection cases (35 ans).
Sources :
– Risk analysis on emerging variants of SARS-CoV-2 carried out jointly by Public Health France and the CNR for respiratory infection viruses, June 15, 2022.
– Epidemiological update: SARS-CoV-2 Omicron sublines BA.4 and BA.5, ECDC, May 13, 2022
– Epidemiological Bulletin, Public Health France
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