While a resurgence of Covid-19 cases is feared this fall, the epidemic no longer seems to scare anyone. Would the arrival of new vaccines and a fairly developed collective immunity be sufficient to stem the wave announced by the specialists? Professor Antoine Flahault, epidemiologist and director of the Institute of Global Health at the University of Geneva, responds to La Dépêche du Midi about a potential shortness of breath.
Among the scenarios, is the loss of momentum or even the end of the epidemic conceivable in the short, medium or long term?
In the short term, yes, the summer epidemic wave is running out of steam, even if France still reports a plateau of nearly 15,000 new cases and 35 deaths per day, i.e. a level twice that of last year at the end of same era. Unfortunately we are not able to predict the evolution of the pandemic in the medium and long term.
Was the epidemic situation the same last year at the same time before the October 2021 wave?
The strong wave of October 2021 was due to the Delta variant which had caused a summer wave of moderate magnitude. If the Omicron BA.5 sub-variant returned this fall and caused a new wave, then we would indeed be in a situation very similar to that of last year.
Could the wave expected in the fall be less than expected? If yes, thanks to what?
No one is able to predict this pandemic accurately more than a week in advance. Now, some of the scenarios envisioned in the past have come true. We have seen three waves in eight months in 2022, so the temptation is great to predict another wave before the end of the year. But we don’t know! It is a possible scenario. For it to occur, a virus and a susceptible, that is to say non-immune, population are needed.
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Regarding the virus, we do not yet see a new variant or sub-variant that could qualify for the fall. He can come fast from anywhere, like Alpha from Kent or Omicron from South Africa. We could see the last BA.5 sub-variant of Omicron come back thanks to the cold season. For that he would have to find a sufficiently large population that is still susceptible, after the summer wave it is not certain that this is the case in Europe today. A prolonged lull cannot be ruled out pending a new variant. All scenarios are on the table, from a prolonged lull to the return of a new wave that could very well be strong.
Will the vaccines against Omicron make it possible to eradicate or stem a possible fall wave?
Available vaccines have never eradicated pandemic waves. They have made it possible to lower the severity of Covid, without sufficiently preventing its transmission. One of the unknowns in which we find ourselves concerns the immunity acquired with the Omicron variant. Some studies evoke a “stealth variant”, which would pass under the radars of immunity. That is to say, without leaving any immune memory of its passage through our body. In this case, adding a valence to the vaccine that would be specifically directed against Omicron would be a waste of time and would bring no benefit compared to the original vaccines. Other studies are more optimistic and suggest a promising future for these new vaccines. It is too early to decide. In a few weeks, with the experience of the Americans, we will know more.
How should the population act in the face of this lull?
It is difficult to ask the population to maintain a high level of vigilance when the virus is circulating less. We see it, people relax their efforts, want to live again as before and it is understandable. Vulnerable people must continue their prevention efforts, for others it is difficult. On the other hand, it is up to the authorities to be vigilant during these periods of calm. They must keep their health surveillance systems on high alert. The authorities could also take advantage of this period to improve the quality of indoor air, the ventilation of closed places, which would make it possible to prevent future waves whatever the new variants. Unfortunately, the authorities tend to manage crises (effectively, moreover) rather than to prepare for the future and invest in prevention and anticipation.