Collective Defense, a Fading Dream

Collective immunity against Covid-19, a pure mirage? Or will we be able to build this dam to stop the spread of the SARS-CoV-2 virus? Promised at the beginning of the pandemic, this protective barrier appears to be dismantling, as new forms of the coronavirus appear, are always more contagious, and spread around the world. Hopes have been revived with the arrival of vaccines in early 2021.

This peaceful horizon was drawing to a close, and we began to dream of a world free from the COVID-19 pandemic, thanks to mass vaccinations and frequent exposure to natural infections. With vaccines, successive waves were going to end well, it was hoped, allowing us to build up gradual, effective lines of defense against the microbial invader. Thus a substantial part of the world’s population will be protected from coronavirus, liberating humanity from this crisis. But the surge of new variants has dampened this optimism.

Will the outbreak of the Omicron wave boost this collective immunity? Even more infectious than its distant cousin the delta variant, which is itself already very permeable, this newcomer appears to unite, under its nanometric envelope, two favorable conditions. On the one hand its diffusion power is conducive to collective defence. On the other hand, its less seriousness – a priority – may offer this patron shield at a lower cost to society.

Health Minister Olivier Veran himself revived this hope: , This fifth wave may be the last, he declared Sunday newspaper January 2. Omicron is so contagious that it will affect all of the world’s population. This will increase immunity: after its passage we will all be more armed. ,

Is the current wave really the last? Experts remain vigilant. “The Minister of Health is in his role: at the beginning of the year, he wants to give hope, two years after the start of the epidemic to show a favorable horizon”, Analysis of Mirce Sofonia from the University of Montpellier. The health minister, however, was careful to weigh a ” Maybe “ This idea of ​​the last tidal wave. to claim that the current wave is the last “A claim is not based on scientific data”Judge this epidemiologist.

Science, in fact, explains a clear antinomy: it shows why, on the one hand, the mirage of collective immunity disappears as we think we are getting closer to it; But on the other hand, it tells us why, despite this despair, it is no longer forbidden to hope. Ultimately, SARS-CoV-2 may, in winter, join the four other seasonal coronaviruses responsible for tonsillitis and mild colds – for how long, that’s another matter. From now on, “The goal is no longer eradication of the virus, but severe forms”, summarizes Arnaud Fontanet, epidemiologist, member of the COVID-19 Scientific Council and director of the Institut Pasteur’s Department of Global Health.

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