Flu Season is Here

Wintertime is flu season in North America. The virus is spread from person to person, either by droplets released during coughing, sneezing, or talking, or by touching an infected surface then rubbing your eyes, ears, or lips. While timing and duration vary each year, January and February are the historical high points for influenza activity. This is according to the Centers for Disease Control and Prevention (CDC), who also report that influenza is responsible for about 200,000 hospitalizations and 23,000 deaths annually.

Based on early data, this year’s epidemic may be a bad one. Latest figures released by the CDC show that influenza-like illness (ILI) is already widespread in 43 states. The influenza A (H3N2) viruses are the most common, and these strains tend to be associated with more severe illness. Even more bad news, this season’s H3N2 vaccine seems to be a genetic mismatch with the strains most commonly reported. Nevertheless, a less-than-ideal match can still provide some protection, and the CDC recommends vaccination for everyone 6 months of age and older.

So how does a mismatch occur? Predicting the right viruses to include in the vaccine formulation is a challenge each season. Due to long manufacturing leadtimes, producers must anticipate the formulation months in advance. The most prevalent manufacturing method (used for the past 70 years) relies on large quantities of hen eggs to incubate viruses. In some cases, the virus can change genetically after the vaccine formulation has been selected.

In 2013, a new production methodology was approved called recombinant technology. Recombinant methods are much faster because they do not depend on egg incubation and grow vaccine proteins in insect cells. For more information, visit the Centers for Disease Control and Prevention 2014-2015 flu facts website at http://www.cdc.gov/flu/about/season/index.htm.

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