And new? The beginning of a new wave of Covid-19 could take shape on the next epidemiological curves. For six consecutive days, the number of cases has been on the rise, with an increase of 41.1% on November 18 compared to last week, indicates Public Health France. As of November 19, there were 47,088 contaminations and more than 730 patients diagnosed with Covid-19 admitted to hospital daily. Added to this is a slight rise in the incidence rate (number of cases per 100,000 people) which stands at 287, or 11.1% more in one week. “Covid deaths are no longer falling and should rise in the coming weeks in France”, reports to L’Express epidemiologist Antoine Flahault, director of the Institute of Global Health and professor at the Faculty of Medicine of Geneva.
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This new stimulus comes almost by surprise since the strike of biologists, angry at the savings that the government still intends to impose on them, prevented the rise of PCR test results for several days. This was the case at the end of October, then from November 14 to 16 when they closed their laboratories, and during the two public holidays of November 1 and 11, during which very few tests were carried out. Consequence: the number of positive cases was, for several days, artificially low. As of November 16, for example, the positivity rate had increased by (only) 9.6%. It is currently at +23.2%.
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If it is possible that the beginning of an epidemic recovery has passed under the radar, this ninth wave can be explained by several factors: the return of school holidays, the drop in temperatures and the spread of the Omicron BQ.1.1 variant in France. This BA.5 sub-lineage seems to be gaining traction in all metropolitan areas. “The highest levels are those of Île-de-France, but the speed of increase seems to be slowing down”, estimates Public Health France. BQ.1.1 represented, on October 24, 32% of the positive cases passed to “sequencing”, according to the last Flash survey.
Like its predecessors, the BQ 1.1 variant proliferates thanks to “a permanent game of escape from the virus with neutralizing antibodies”, underlines Hervé Fleury, virologist and professor emeritus at the CNRS and the University of Bordeaux. Bad news: BQ.1.1 seems to be able to “evade” vaccination more and to infect people who have already been infected more easily, according to “in vitro” studies. For this, “the variant has three mutations, 346, 444 and 460, which are important escape mutations”, and are present in the binding domain of the spike protein to the receptor which serves as a gateway into the cells, unfolds the virologist. Good news, however: BQ.1.1 does not seem more virulent than the previous variants, according to the latest studies.
“A new wave throughout Western Europe”
This variant is not the only one in circulation. Without achieving the same success, “more than a hundred BA.5 sub-lineages are currently circulating in France, illustrating the diversification within this sub-lineage”, adds Public Health France. And France is not an isolated case.
“All the epidemiological indicators are currently converging in favor of the arrival of a new pandemic wave throughout Western Europe”, assures Antoine Flahault. In a report from the European Center for Disease Control and Prevention (ECDC), published on October 21, modeling suggests that Covid-19 cases attributable to BQ.1 and BQ.1.1 will, between mid-November and early December, represent more than half of infections. And at the beginning of 2023, still according to the ECDC, it would be more than 80% of the cases on the European continent. Moreover, BQ 1.1 would cause symptoms close to gastroenteritis, which could complicate the monitoring of the epidemic.
Jacques Izopet, head of the virology department at the Toulouse University Hospital, is more reassuring. “It is still too early to speak of a ninth wave. In the south of France, the weather is still good and we have not seen an upsurge in the number of cases. The indicators are not worrying. The specialist admits that he would be more concerned if this resurgence of the epidemic was carried by a new variant – genetically different from Omicron – but, in the case of BQ.1.1, “we can hope that this resurgence will be as well controlled than the previous one”. Besides, does it still make sense to speak of a “ninth wave”? The question, for Jacques Izopet, arises: “the notion of wave is linked to the influx of hospitalized people. If they are smaller, we can no longer really speak of waves.”
The arrival of new vaccines as a firewall?
Regardless of the name given to it, another pressing question: what form will this epidemic recovery take? “The vaccine still seems effective in reducing the risk of serious forms and, hopefully, of long Covid. However, it should not be able to prevent this new wave from surging in the weeks to come”, underlines Antoine Flahault. Another important parameter to understand the evolution of this new recovery: the number of target people who received the new vaccines adapted against the sub-variants of Omicron BA.1, BA.4 and BA.5. For the moment, only “10 to 15%” have been bitten again. An insufficient rate, regretted the Minister of Health François Braun. However, these new so-called “bivalent” vaccines could generate more effective antibodies against BQ1.1. “On a theoretical level, it is possible”, adds Hervé Fleury.
If abnormally severe forms are not reported, concern remains for the elderly and immunocompromised. “BQ.1.1 escapes monoclonal antibodies used for immunocompromised people, which can lead to treatment problems,” says the virologist. From there to justify the introduction of the wearing of the mask compulsory for all, in closed places and public transport? “I don’t think so, replies Jacques Izopet. For the moment, the rules of common sense are justified, but if the number of cases were to increase, it would seem logical to me to protect yourself by wearing a mask, for example.” Hervé Fleury is firmer on this question: “Since this summer, I have been saying that we have to wear the masks again. There are people who have been vaccinated four times and who are going to be infected.” It remains to be seen whether the Covid-19 will disrupt the end-of-year celebrations for the third consecutive year.