Why a Mutated Virus Could Put a Nasty Bite Into This Flu Season

— -- Get ready for lots of sniffles and sneezing now that flu season has officially arrived -- and it could be a nasty one.

The U.S. Centers for Disease Control and Prevention warned today this flu season could be severe due to mutations and a particularly virulent flu strain that was found to be prevalent only after this year's influenza vaccine already went into production.

After looking at approximately 1,000 flu virus samples, CDC officials said that the H3N2 virus was the most common strain of flu. The virulent variety was predominant during three of the last ten years when influenza mortality was the highest.

"It's too early to say for sure that this will be a severe flu season, but Americans should be prepared," said CDC Director Dr. Tom Frieden. “We can save lives with a three-pronged effort to fight the flu: vaccination, prompt treatment for people at high risk of complications, and preventive health measures, such as staying home when you’re sick, to reduce flu spread.”

Additionally, some of the virus strains mutated slightly after this year's influenza vaccine was being manufactured. The influenza vaccine produced this year provides approximately 50 percent protection against the H3N2 strain, which is currently causing the majority of flu cases, CDC officials said.

Dr. Kathlyn Edwards, a professor of pediatrics and director of the Vaccine Research Program at Vanderbilt University School of Medicine, said children infected with H3N2 generally have worse flu symptoms than most other flu strains.

“If you compare children with confirmed infections with H3N2 and H1N1, by and large the H3N2 children will have a higher fever and feel worse in general,” Edwards said.

While the flu vaccine may not provide complete protection against H3N2, Edwards said it is imperative that people don’t give up on the flu shot.

“You should go ahead and get vaccinated because there are other strains in there,” Edwards said of the vaccine. “There may be some protection from a strain that is not a perfect match but that it’s cross-reactive,” to the virus.

The CDC also recommends that anyone with flu symptoms head over to their doctor promptly to be treated with an antiviral medication such as Tamiflu. Since these medications only work within 48 hours of the start of symptoms, the CDC said it’s key to get the antivirals early.

Common symptoms of the flu include fever, sore throat, cough, runny nose, body aches and chills.