CDC: New flu strain makes this year\'s flu shot less effective

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COLUMBIA - The CDC says this year's flu shot is not as effective against the current, most common influenza strain.

In samples collected from Oct. 1 to Nov. 22, the CDC found 52 percent of flu cases were caused by a virus different from the strain contained in the vaccine. It attributes this to a mutation or shift of the strain.

Most cases of the flu so far this year are influenza A (H3N2), which has been linked to "higher overall and age-specific hospitalization rates and more mortality have been observed, especially among older people, very young children, and persons with certain chronic medical conditions compared with seasons during which influenza A (H1N1) or influenza B viruses have predominated," the advisory said. Influenza A was also the most common virus during the 2012-2013 flu season. The Columbia/Boone County Department of Public Health and Human Services said this strain is most common in Boone County this year as well.

"We have seen an increase overall in Boone County - a significant increase- of the amount of influenza, specifically type A, which is the H3N2, coming into the county that have been reported," Public Information Officer Andrea Waner said.

While vaccine isn't as effective to prevent this particular strain of flu, the advisory says it can still reduce some severe flu symptoms like hospitalization and death. The CDC still recommends getting vaccinated to help prevent the other, less common flu strains, and the health department agrees.

"We're definitely still recommending that people come in and get vaccinated," Waner said. "We have a full supply of vaccine available, and it's better to just go ahead and take those steps, those preventative measures, and get vaccinated than to not be vaccinated at all." 

Waner said there is always a predominant viral strain every flu season, but she and the CDC suggest extra preventative measures should be taken this year. The CDC emphasizes the importance of early use of antiviral medications, like Tamaflu and Relenza, to treat and reduce flu symptoms. Clinical trials have shown these medicines can shorten the duration of fever and illness symptoms, reduce the risk of complications from influenza like pneumonia, and reduce the risk of death among hospitalized patients.

"They recommend people, especially high risk people- people with heart disease, lung disease, diabetes, asthma, pregnancy, things like that- if those people start seeing that they have flu like symptoms to go ahead an contact their physician and seek out some antiviral treatment. That's a big thing that the CDC says is going to be very important this year is for people to be prescribed antiviral treatments."

A little over 12,000 people were hospitalized and 149 children dies of the flu during the 2012-2013 season. About 90 percent of those children were not vaccinated. 

Waner says the department is still seeing a steady stream of people coming in for flu shots.

"It tends to die off sometimes this time of year because people think 'oh flu season's almost over, and I don't need to be vaccinated,' but that's not true. We want you to come in and still be vaccinated. Flu peaks in January and February, so you still have a little bit of time left."