PITTSBURGH —

A new strain of influenza is causing a vaccine mismatch, but experts assure that the flu shot still offers protection against severe illness.

Fever, chills, sore throat and cough are common symptoms indicating that flu season is officially here. Advertisement

The flu vaccine covers three strains of the flu and does not contain any live flu virus. However, the H3N2 strain has mutated, leading to a mismatch with the current vaccine.

"This season, one of the strains, the H3N2 strain, seems to have mutated away from what was predicted to be the case, and that's created a vaccine mismatch," said Dr. Amesh Adalja, a senior scholar at the Johns Hopkins Center for Health Security and a Pittsburgh-based infectious disease physician.

Despite this, Adalja said the vaccine is still

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