I’ve always thought that the idea of the flu being more common in the winter was just an old wives tale. But apparently, not only is it actually true, but experts now know why.
A new study found that influenza germs last longer and pass from person to person more effectively in lower absolute humidity, when it’s cold outside and the air is dryer. Absolute humidity is a measurement of the total amount of water vapor in the air at a given temperature.
Earlier studies of humidity as it relates to the flu focused on relative humidity – the ratio between water vapor present and the air’s saturation point – and found no link.
The study was led by Jeffrey Shaman of Oregon State University. The findings appear in the Journal Proceedings of the National Academy of Sciences.