The cold may not be sending many people to the hospital for prolonged exposure, but the extended sub-freezing temperatures are promoting an especially intense flu season.

“We had a very strong upsurge in the last two weeks of patients admitted to literally every hospital in Davidson and the surrounding counties,” says Vanderbilt’s William Schaffner, who oversees regional flu monitoring for the Centers for Disease Control.

As of Tuesday, the
latest influenza map from the CDC didn’t include the most current data for January, and Schaffner points out that the figures are just the “tip of the iceberg,” because patients have to be admitted to a hospital and test positive for the flu. Some patients come to clinics and get treated because their symptoms are enough to prove they have the virus.

According to hospital spokespeople, Saint Thomas Midtown has twice as many patients testing positive for the flu compared to last year. Saint Thomas West has treated 30 flu patients since Christmas. The Emergency Department director at Nashville General describes “tons of flu” cases, even for this time of year. The current flu outbreak is being described as “moderately severe.”

The prevalence has led some school systems to delay their return from Christmas break, including
Maury,
Stewart and
Lincoln counties.

The cold weather does play a role, Schaffner says. For one, people stay inside where they’re more likely in close quarters. And
new research shows the virus hops around more in the cold, dry air.

“The flu particles that we exhale have been demonstrated to hover in the air for longer periods of time, so that makes it easier for it to be inhaled by someone else,” says Schaffner, who is one of the country’s leading flu experts.

As for the extreme temperatures, Vanderbilt has treated a patient with cold-related exposure. TriStar Centennial confirms a couple of frostbite cases, but they were mild enough that they could be resolved with rewarming treatment.