Professor Jean-François Delfraissy, immunologist and also president of the National Consultative Ethics Committee (CCNE) since 2016, took over the presidency of the Covid-19 Scientific Council in March 2020, in order to advise the government in the fight against the pandemic . He comes back for The world on the different possible evolution scenarios.
Despite the start of the school year and the return of the French to the office, the number of cases continues to decline. Are you surprised?
Yes. We hadn’t expected that the fourth wave would slow down so quickly. This is partly explained by the very high level of vaccination in France and by the very high efficacy of vaccines, of unexpected magnitude. There are probably other factors that are somewhat beyond our control. This does not mean that the fourth wave is completely behind us, however. With the arrival of autumn, behavior changes, we live in an enclosed environment, a resumption of viral circulation is therefore possible.
Should we fear a new wave?
In the coming weeks, two scenarios are possible: either a small wave of the Delta variant, with a contained impact on the healthcare system, or a significant increase in viral circulation, but without major impact on the healthcare system. I am therefore quite optimistic, even if we cannot totally exclude the appearance of a new variant. As long as we keep the barrier gestures, we should be able to cope with a recovery.
In the medium term, the virus could become endemic, or even seasonal, both because the Delta variant is contained by the vaccine and because its capacity to evolve is limited. The other possibility is the emergence of a variant which is even more transmissible or which would escape the immunity conferred by the vaccine. In the long term, of course, the crisis is not over.
When can we let our guard down?
The government has chosen a gradual easing of the restriction measures – an end to the health pass in certain places – from November 15 rather than immediately, this is the scenario we recommended. We maintain two weak points: in France, the vaccination of over 80s remains to be improved [elle est de 86,4 % pour la première dose], and there is probably a loss of vaccine efficacy after six months in those over 65 years of age. This is why vaccination with a third dose must be accelerated; it has so far only affected 35% of eligible over 65s six months after the last dose.
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