10:45 p.m., March 19, 2022
Bruno Lina is a virologist and member of the scientific council. As the cases of Covid-19 go up in France, he explains that the current increase is the extension of the fifth wave and that the Omicron variant, although less virulent, is not an ordinary virus.
Is the current epidemic rebound taken seriously enough?
Since the start of the pandemic, to estimate the impact of epidemic waves, the number of hospitalized patients has been used as an indicator. It is the most stable and robust indicator. This remains true today despite the decline in the use of PCR tests. In Denmark and the United Kingdom, in the two European countries currently ahead of stage compared to France, the spread of the sub-variant of Omicron BA.2 has favored a resumption of incidence. Yet while the transition from BA.1 to BA.2 coincided there with the loosening of barrier measures and the reopening of society, there was no significant increase in the hospitalization rate. Except for a few days in some parts of the UK. This absence of a serious signal from our neighbors led the French authorities to lift the obligation to wear a mask indoors and that of the vaccination pass on March 14.
Does this mean that the epidemic is over as some have claimed?
Admittedly Omicron is less aggressive than Delta or Alpha but one should not draw the erroneous conclusion that it is a banal virus and not very dangerous. The epidemic is not over; wave BA.2 is the extension of the fifth wave because we have never fallen below the threshold of 500 new positive cases per day per 100,000 inhabitants on average over seven days as in the calm period of June 2020 or the beginning of summer 2021.
What is the share of BA.2 in viral circulation?
According to our latest estimates, this sub-variant of Omicron, which became the majority in February, now represents between 75 and 95% of infections. There is nothing surprising because it is 30% more transmissible than BA.1. He goes very fast; this is unheard of for a respiratory virus. If such a pathogen had arrived in March 2020, it would have been chaos. Fortunately, it does not escape immunity any more than its predecessor, the BA.1. The vaccine efficacy remains unchanged according to the English and Danish data.
Read also – Covid-19. Variant BA.1 and BA.2 from Omicron: where are we in France?
In recent days, hospitalizations have increased across the Channel or in the north of France. Should we be worried about it?
In Denmark, the daily incidence peaked at 800 new cases per 100,000 population and yet there was no hospital embolization. Admittedly, hospitalizations are on the rise again in the London region and in Scotland. Even if we are very attentive to what is happening there, the situation has nothing to do with that of spring 2020 and 2021. In our country, the number of hospitalizations will certainly increase temporarily, but the situation should remain under control. Because, in two years of pandemic, the environment in which the virus circulates has changed. We know how to take care of patients with Covid-19 and prevent complications through preventive treatments. And above all, even if it remains imperfect, the collective immunity induced by vaccinations or past infections protects us against serious forms.
Why were the restrictions not maintained for a few more weeks?
The hospital indicators were green when the decision to lift them was taken. The end of the obligation to wear a mask is often misinterpreted as the obligation to no longer wear it. What a strange relationship to individual freedom and standards we sometimes have! The virus has regimented our lives enough; it is there forever, yet we cannot always live under duress. On the other hand, each of us can continue to wear it in closed or crowded places to protect ourselves and the most fragile. Thinking about airing is also a civic act. This is getting used to living with Sars-CoV-2.
How do you envision the next few weeks?
Thinking of escaping the risk of infection by Sars-CoV-2 is like saying to yourself that you will not inhale polluted microparticles when you live in a big city! Everyone is exposed, and Omicron increases this risk. It is estimated that it has already infected more than 20 million French people. There is no escaping immunization against this virus. Currently, thanks to the immunity acquired by vaccination or previous infections, the majority of people are affected by minor clinical forms: runny nose, headaches, digestive disorders, fatigue. It is not the same for the non-immunized who risk severe forms.
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Thinking of escaping the risk of infection by Sars-CoV-2 is like telling yourself that you will not inhale polluted microparticles
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Are reinfections frequent?
It is too early to give a precise answer. Omicron-Omicron reinfections would represent a very small number of cases. We assume strong short-term protection. It is likely that young people infected in January will not be struck again in March because their immune system will protect them at least for a few months, but the risk varies between individuals.
Could the first round of the presidential election fall in full swing?
The modest rebound linked to the circulation of BA.2, the relaxation of barrier measures, the cold climate and the end of school holidays came a week earlier than expected, starting on February 22. What will be the impact of the multiplication of social contacts? No one knows and therefore cannot predict the dynamics of the epidemic. The scientific council analyzed the different scenarios developed by the team of Simon Cauchemez at the Institut Pasteur according to the intensity of the increase in social contacts. Both the most optimistic and the most pessimistic are the least likely. In any case, the peak should remain much lower than that of January. According to us, we could exceed 100,000 daily cases [la moyenne actuelle sur une semaine était d’environ 82000 avant-hier] before experiencing a slow decline. It is illusory to imagine that the incidence is nil in mid-April.
Read also – Covid-19: do we really have to drop the mask?
Are the elderly and frail sufficiently protected against the BA.2 wave?
For them, in the event of infection, access to early treatment such as the antiviral drug Paxlovid, which prevents complications, should be promoted. However, the most important measure is vaccination, which protects them against the risk of a severe form. This is why the government has decided to offer them a second reminder. In an opinion issued the day before yesterday, the High Authority for Health, the body responsible for the vaccine strategy, believes that it is necessary to go further by offering this fourth dose to those over 65 who are most at risk, because the English and Israeli data show that recall effectiveness begins to decline after three months in people over 60 years of age.
Does the very late flu also threaten the elderly?
Sure ! The circulation of Sars-CoV-2 and the wearing of masks have undoubtedly contributed to delaying this seasonal epidemic. Strain A (H3N2), which is currently circulating, affects the most fragile and the oldest. And as the flu vaccination was done six months ago, the risk of infection is greater than in January or February. Although far from harmless, the flu remains a less dangerous threat than Covid-19.
Containing a respiratory virus requires convincing infected people to self-isolate. Are we still capable of it?
It’s a snake biting its tail: the clinical forms are less severe with Omicron, so the feeling of the need to isolate oneself is less strong, which means that we infect more, maintaining the epidemic. This virus is highly transmissible and, like the previous variants, contagious before symptoms appear. I urge infected people to isolate themselves for at least five days, which considerably reduces the risk of transmission.
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Declaring the virus endemic does not mean the problem is solved
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The transition to a so-called “endemic” phase seemed to carry for some the promise of a virus-free spring-summer. What’s going on ?
The wishful thinking of taking for granted our desire for the epidemic to be behind us, combined with a lack of general scientific culture, has led to an error of judgment: declaring that the virus is endemic does not mean that the problem is solved. . A pandemic virus circulates all over the planet without limit in time and space. Then, thanks to the gradual building up of herd immunity, it changes its behavior, perhaps switching to a more seasonal rhythm. But this is not a one-way trip; this transition is gradual.
China, whose management of the first two years of the pandemic had been praised, is struggling. What lesson should we draw from this?
Because of its extreme transmissibility, Omicron frustrates this policy. The logic of zero Covid is untenable in the long term for a country that has failed to install very high level immunity through vaccination. Only New Zealand, which also has the advantage of being an island, seems to have really succeeded in this bet. It will undoubtedly be the big winner in the management of the pandemic when the time comes to take stock of it.