Variant BA.5 Covid: a first vaccine validated in France

Variant BA5 Covid a first vaccine validated in France

BA.5, a sub-variant of the Omicron variant, was still the majority in France in mid-September. The HAS approves the use of a new vaccine from Pfizer targeting the BA4 and BA5 lineages.

[Mise à jour le 20 septembre 2022 à 18h34] 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. Now ubiquitous, this variant has five sublineages of which the BA.5 which represents 93% of positive tests in France in September. On September 20, the HAS gives its authorization to the distribution in France of a new vaccine from Pfizer targeting the BA4 and BA5 sublines. This vaccine mRNA is reserved for use for the booster dose only. This campaign will concern people at risk of severe form of the disease as well as to those around them and to healthcare professionals. This bivalent vaccine (which targets the original strain of Sars-Cov-2 and the Omicron sublines) is not a new vaccine but an adapted vaccine circulating strains, much like the flu vaccine that changes every year. Among theare symptoms the most common, the fatigue, cough and fever.

What is the BA.5 variant?

BA.5 is a sublineage of the Omicron variant of Covid-19. It began to be identified in January and February 2022 in South Africa according to ECDC; early April according to Public Health France. It aired at Portugal, leading to a new wave of Covid-19 in May that was particularly virulent for the over 80s. He is particularly watched because he has L452 mutations (like the BA.4) associated with the increased transmissibility of Delta.

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. HASInstead of lasting an average of 4 days, they last rather 7 days or even 10 days so we contaminate longer“explained Dr. Damien Mascret on June 27. A new symptom is reported by Professor Luke O’Neill of Trinity College Dublin (Ireland): night sweats : “The disease is different because the virus has changed, night sweats being a new symptom“said the immunologist on Irish radio Newstalk July 7.

Age and symptoms of BA.4 and BA.5 cases compared to BA.1 cases as of June 15 © Public Health France

How long do symptoms of the BA5 variant last?

The duration of clinical signs is on average 7 days for the cases of BA.4 and BA.5 versus 4 days for other Omicron cases.

Are vaccines effective against the BA.5 variant?

On September 20, the HAS gives its authorization to the distribution in France of a new vaccine from Pfizer targeting the BA4 and BA5 sublines. This vaccine mRNA is reserved for use for the booster dose only. This campaign will concern people at risk of severe form of the disease as well as to those around them and to healthcare professionals. This bivalent vaccine (which targets the original strain of Sars-Cov-2 and the Omicron sublines) is not a new vaccine but an adapted vaccine circulating strains, much like the flu vaccine that changes every year. ).Expected clinical efficacy for these new bivalent vaccines is at least equivalent or even superior to that of the original monovalent vaccines” indicates the Authority, Regarding the people under 30, HAS maintains its recommendation to use only Comirnaty® vaccines (Pfizer BioNTech).

What is the rate of the BA.5 variant in France?

In September, the Omicron variant is dominant in France and its BA.5 sub-lineage has been the majority for two months now. In mainland France, BA.5 (all sub-lineages combined) represented 93% of interpretable sequences during the August 22 Flash survey, reports Public Health France September 15. BA.5 is also in the majority internationally, illustrating its higher competitiveness compared to BA.2. The Omicron BA.4 sublineage continues to circulate in the world and in France, but at lower levels than BA.5. In mainland France, he represented 6% interpretable footage from the August 28 Flash investigation.

Omicron sub-lineages in France
Omicron sub-lineages in France © Public Health France

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“, explained Yves Buisson, president of the Covid cell of the Academy of Medicine on Europe on June 7. The symptoms last longer (7-10 days)”so we contaminate longer“explained Dr. Damien Mascret June 27.

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. “In South Africa, a study comparing case fatality rates [proportion de décès liés au BA.5] during the different waves showed a fatality rate of 7.1% over the BA.4/BA.5 circulation period, against 10.9% during the circulation of BA.1/BA.2” reports Public Health France September 7. A first study from South Africa reported by Santé Publique France on July 6 comparing the risk of serious events between the Omicron BA.1 wave and the BA.4/BA.5 wave had shown that the risk of hospitalization/death was less in previously infected cases (70% lower) or vaccinated 3 doses (83% lower) compared to uninfected/vaccinated cases. “The median length of hospitalization (for BA4 or BA5 cases, editor’s note) is 5 days“indicated Public Health France on June 15.

What treatments are effective if you are contaminated with the BA.5 variant?

the Paxlovid remains the first-line curative treatment regardless of the variant or sub-variant of SARS-CoV2. “Its activity is not modified vis-à-vis BA.4 and BA.5 compared to the BA.1 and BA.2 sub-variants” confirm the General Directorate of Health July 11. This antiviral is administered orally. It can be prescribed by any doctor, and is available in health facilities and pharmacies pharmacy since February 2, 2022. In the event of contraindications to Paxlovid (in particular related to drug interactions), the treatment Evusheld (tixagevimab 150 mg/cilgavimab 150 mg) is available. It is administered in healthcare facilities by the intramuscular route. “In French patients treated with Evusheld, seroneutralization seemed weaker for BA.5 compared to BA.2. Neutralization levels decreased over time, at a faster rate for BA.5 emphasizes Public Health France.

Sources:

– Risk analysis on emerging variants of SARS-CoV-2 carried out jointly by Public Health France and the CNR for respiratory infection viruses, September 7, 2022.

– Risk analysis on emerging variants of SARS-CoV-2 carried out jointly by Public Health France and the CNR for respiratory infection viruses, August 10, 2022.

– Risk analysis on emerging variants of SARS-CoV-2 carried out jointly by Public Health France and the CNR for respiratory infection viruses, July 6, 2022.

– 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

– Kislaya I, Casaca P, Borges V, Sousa C, Ferreira BI, Fernandes E, et al. SARS-CoV-2 BA.5 vaccine breakthrough risk and severity compared with BA.2: a case-case and cohort study using Electronic Health Records in Portugal. medRxiv. 2022:2022.07.25.22277996.

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