New H3N2 flu variant raises concerns as winter approaches

• Health officials in Canada, Japan and the U.K. have already warned of a wave that's sending people to the hospital.

State of play: Seasonal influenza activity has increased slightly in the U.S. but remained low through mid-November, according to the Centers for Disease Control and Prevention.

• The number of flu-like illnesses in Ohio has also been considered "minimal."

How it works: The new H3N2 variant (called subclade K) is a strain of influenza A. However, it differs from the H3N2 strain used for the existing flu vaccine.

• Symptoms are like the common flu, including a sore throat, runny nose, fever, cough and headaches.

By the numbers: Early research suggests the existing flu shot is about 30-40% effective in preventing hospitalizations for adults with the new strain.

• It is about 70-75% effective for children.

Reality check: Cleveland Clinic cautions that while analysis suggests a mismatch between subclade K and the existing vaccine, "real-world vaccine effectiveness data remains limited."

The bottom line: Both the CDC and Cleveland Clinic still suggest people six months and older get the flu vaccine.