Cold, Low Humidity Cause Rapid Spread of Influenza, Study Says

This year may be a record year in the spread of influenza, and according to researchers, low temperatures and low humidity are to blame.

Researchers at the Mount Sinai Medical School of Medicine studied the rapid spread of influenza on infected and uninfected guinea pigs using seasonal factors that may lead to a wide outbreak, such as indoor crowding and heating during cold weather, seasonal fluctuations in immune system responses, relative humidity, temperature and UV radiation — none of which have been tested before, the study claims.

The study, published in PLoS Pathogens, found that low, relative humidity of 20 to 30 percent caused the virus to rapidly spread. The opposite effect was seen at high humidity levels of 80 percent or above.

Findings also showed that the virus spread easier in 5-degree than in 20-degree Fahrenheit temperatures, and there was no transmission reported at 30 F.