Influenza has remained a mystery in many respects but scientists have finally solved part of the question of why the disease spreads primarily in the winter. It seems that the virus is more stable and stays in the air longer when the air is cold and dry. Flu season in the northern hemisphere is usually from Nov. to March and in the southern hemisphere is usually from May until Sept. Some hypothesis about why this occurs have been:
- In the winter people are indoors spreading infection, however people are crowded together all year round.
- In the winter children are in schools spreading infection, however we don’t usually see flu in Sept., Oct., or May
- There is a decreased immune response in the winter.
The research done at the Department of Microbiology at Mt Sinai School of Medicine does more than just hypothesize. Their research using guinea pigs directly tests the effects of temperature and relative humidity on the transmission of influenza. It is great to finally see some research aimed at understanding the basics of this common infection which is responsible for 36,000 deaths and about 226,000 hospitalizations in the U.S. every year.