It's not the cold that causes the flu

Faced with waves of flu (or even simple colds), a completely false belief is reinforced: it's the cold's fault. If anything, the opposite is true: flu and colds become more common with the arrival of cold weather, as we go out less, spend more time indoors, and have more close contact with other people: all ideal circumstances for the spread of viruses. And it's viruses, not temperatures, that cause colds and flu; if anything, it's the cold It can increase the risk of infections because it tires the body and reduces the immune system's response, but it does not cause the flu.

The only way cold weather can promote the spread of viruses is indirect: in winter, heating makes the air drier, the mucous membranes of the nose and throat dry out and become less effective at blocking viruses and bacteria.

Not surprisingly, rhinovirus (one of the most widespread respiratory viruses in the world), which generally causes colds, with an upper respiratory infection, peaks when children return to school (and not in winter) and germs spread in often poorly ventilated classrooms. A scientific study Part 2007 explains well how  the cold in itself does not cause the flu , while a key factor in the spread of the influenza virus is linked to the humidity of the environment in which it circulates.