H3N2: 2013 Flu Season Update on Deaths, Hospitalizations, and Spread of Influenza

The three-dimensional structure of influenza virus from electron tomography. Image courtesy of the NIH

The three-dimensional structure of influenza virus from electron tomography. Image courtesy of the NIH

Pediatric deaths from the flu weren’t always reported to the CDC. In 2004, however, the government started requiring every state to report all pediatric deaths due to influenza. This flu season, which started earlier than usual, there have been 20 pediatric deaths associated with the flu. According to USA Today, there are on average 100 pediatric deaths each flu season.

H3N2 Responsible For Severe Flu Season in 2013

In their 2004 study, the CDC found that deaths rates were more than doubled during flu seasons where influenza A (H3N2) was dominant than when influenza A (H1N1) or influenza B were dominant strains. This is the case for this flu season. The CDC reports that influenza A (H3N2) has been identified as part of this year’s strain. During the week ending on January 5, 2013, out of 4,222 influenza positive tests, 3,369 of those were influenza A, the other 853 cases were influenza B.

Flu Season: Nothing to Joke About

As you can see from Google’s Flu Trends map, and the CDC’s notice that this is the worst flu season in ten years, the 2013 flu epidemic is serious. The CDC found that influenza A (H3N2) causes more hospitalizations and deaths than other strains of influenza; H3N2 is widespread this year. Many people disregard the flu as anything but serious. But the numbers don’t lie – death rates and hospitalizations paint a clear picture of what influenza can do.


Centers for Disease Control and Prevention. Situation Update: Summary of Weekly FluView. (2013). Accessed January 16, 2013.

USA Today. 100 Kids Die of Flu Each Year. (2013). Accessed January 16, 2013.

Centers for Disease Control and Prevention. Seasonal Influenza -Associated Hospitalizations in the United States. (2011). Accessed January 15, 2013.

Centers for Disease Control and Prevention. Estimating Seasonal Influenza -Associated Deaths  in the United States: CDC study confirms variability of flu. (2011). Accessed January 16, 2013.

© Copyright 2013 Janelle Vaesa, MPH, All rights Reserved. Written For: Decoded Science

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  • James

    This is the first article I have come across that actually publishes the ILI as opposed to just the spread map. If you look at the data from the CDC, aside from the fact that this seasons struck earlier than usual, the numbers are nearly identical to the 2007 season (ILI peaked at 6% before decreasing each following week). The past 6 seasons we’ve hit the “epidemic” level and had an ILI above the national baseline each year, even during last year’s “mild” season.