In March 2020, as in August 1914, we set out for the battlefield. We knew the fight would be hard; there would be casualties, but we trusted it would all be over in three months. What a terrible illusion. A century ago, the Great War lasted four years. Today, five months after the lockdown of Europe and eight months after anxiety started to rise in China, it is hard to say when the COVID-19 epidemic will be behind us.

We know that the virus that causes the disease has a crown-like shape, hence its name. But it also looks very much like a maze — and while epidemiologists have imagined many scenarios, the pandemic isn't following any of them. The number of sick people has again been on the rise for several weeks following a continuing slump, with no parallel uptick in the number of deaths.

Europe, for example, is registering 15 times fewer deaths every day than four months ago. While the virus seemed to prefer older people, it is now being detected mainly in young people. It seemed to thrive in damp coolness, but it has done enormous damage in Brazil. Children are getting sick less often, but scientists still don't know if they are less contagious.

The mysteries of COVID-19 don't end there. While the virus has a perfectly identified genome, how it circulates is still poorly understood. It seems to survive better in the air than we thought. And the mechanisms of immunity remain elusive. Researchers are now investigating the possibility that protection may be provided not only by antibodies, but also by white blood cells.

Governments are forced to fly by the seat of their pants.

The only certainty we have right now is that we're not done with this virus. Even though Donald Trump promised a vaccine before the U.S. presidential election in early November, it is difficult to know when this decisive tool in the fight against an epidemic will be available, or even how effective and long-lasting it will be.

In this dense fog, governments are forced to fly by the seat of their pants, between the risk of inaction and the risk of appearing to cry wolf. Business leaders, for their part, have no choice but to be hyper-agile to adapt to a constantly changing health situation. And it's not just a matter of weeks. According to Microsoft founder Bill Gates, who is now devoting part of his immense fortune to vaccine manufacturing, "for the rich world, we should largely be able to end this thing by the end of 2021, and for the world at large by the end of 2022."

This prognosis seems reasonable today. Even if, like the First World War, the virus has demonstrated a formidable ability to beat the prognosis.

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