As Norovirus and Flu Cases Rise, Know These Symptoms to Tell the Difference

With new variants of both flu and norovirus spreading in the U.S., it worth knowing the symptoms of each viral illness — and the best ways to prevent getting sick in the first place.

And, considering the last flu season was the most severe the U.S. had seen in 15 years, some experts are concerned that this winter may be similarly challenging.

The new flu variant — called "subclade K" — is a type of H3N2, an influenza A strain . It caused severe flu outbreaks elsewhere in the world, including Japan, Canada and the U.K., before making its way here, Dr. Robert Hopkins Jr., medical director of the National Foundation for Infectious Diseases, told TODAY.com recently.

While our annual flu vaccines do provide some protection against H3N2 strains, infectious disease experts worry that thi