An engineer works on a sample at the Pasteur institute's biological emergency response cell (Cellule d'intervention biologique d'urgence - CIBU) in Paris, on April 23, 2024. With millions of visitors expected in France this summer, the Olympic Games will potentially bring together as many people as pathogens: bacteria, viruses and other parasites... At the Institut Pasteur, a team is on standby to track them down when the time comes, if necessary. (Photo by Alain JOCARD / AFP)