Much of the Northern Hemisphere is currently in a deep freeze, thanks in large part to a Polar Vortex in the Arctic. As I write this, I am bundled up because outside it's -35ºC (-31ºF), and I just hope I don't catch a cold. It turns out that the old adage about catching a cold when it's actually cold outside is true. IFLScience reports that the rhinovirus "multiplies more efficiently in the cold." Because the nasal cavity is generally a few degrees cooler than your lungs, that's where the rhinovirus prefers to bump uglies: hence, your snotty nose. Now a new study has determined that it's not just that the virus prefers the cold: our immune response isn't as good when the temperature plummets.
Yale’s Akiko Iwasaki and colleagues ... exposed the cells that line the airways of mice to a rodent version of the rhinovirus strain at either 33 degrees or 37 degrees Celsius. Then they examined the viral replication and antiviral responses that were mounted by the immune system in the cells targeted by the virus ... during replication, the virus prompted more robust immune responses at the warmer temp." Iwasaki concluded that “The innate immune response to the rhinovirus is impaired at the lower body temperature compared to the core body temperature,” and “it’s not just virus intrinsic, but it’s the host’s response, that’s the major contributor." So all those times my mammy told me to bundle up and put on a woolly jumper "or you'll catch your death out there," she wasn't wrong.
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