CDC: 2014-2015 Flu Season May Be Severe

Roughly half of the influenza A viruses (H3N2) collected in the 2014-2015 flu season are drift variants, viruses that are genetically different from the virus found within this year’s vaccine.

According to the CDC, years in which H3N2 viruses are most common are often associated with a higher number of hospitalizations and deaths from the disease, even when the vaccine matches the circulating strain. The strain was most prominent in the 2012-2013, 2007-2008, and 2003-2004 seasons—all of which had the highest mortality levels in the last 10 years.
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Although the vaccine does not match the current circulating strain exactly, the CDC urges that individuals still get vaccinated. Those who are vaccinated may have milder illness than those unvaccinated, as was seen during the 2007-2008 season. That year, despite a predominant H3N2 virus that was also a drift variant, the vaccine showed overall efficacy of 37% and 42%.

“Vaccination has been found to provide some protection against drifted viruses in past seasons. Also, vaccination will offer protection against other flu viruses that may become more common later in the season,” said researchers.

The CDC has also stressed that antiviral treatment be employed in high-risk individuals presenting with flu symptoms, even before confirmation of influenza.

“It’s too early to say for sure that this will be a severe flu season, but Americans should be prepared,” said CDC Director Tom Frieden, MD, MPH. “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.”

—Michael Potts

Reference:

CDC. Early data suggests potentially severe flu season [press release]. December 4, 2014. www.cdc.gov/media/releases/2014/p1204-flu-season.html. Accessed December 5, 2014.