So you thought flu was done for the season? Not quite. National influenza-like illness activity actually increased during the second week of March in the eastern states. Eight states reported widespread geographic influenza activity for the week.
Five states (Maryland, Mississippi, New Jersey, Texas, and Virginia) and New York City reported moderate activity. Influenza activity continues to decline across much of the rest of the country. The proportion of people seeing their health care provider for flu-like illness increased slightly and remains above the national baseline.
The number of newly reported hospitalizations is leveling off. The highest number of reported cases continues to occur among people 65 and older, who account for more than half of all reported hospitalizations. The proportion of deaths attributed to pneumonia and influenza in 122 cities decreased again this week, but still remains slightly above the epidemic threshold.
Influenza A (H3N2), 2009 influenza A (H1N1), and influenza B viruses have all been identified in the U.S. this season. While influenza A (H3N2) viruses remain the predominant strain overall, the proportion of influenza B viruses has increased in recent weeks. For the week reported, influenza B accounted for 64% of all influenza viruses reported.
Since October 1, 2012, the Centers for Disease Control have tested 377 2009 influenza A (H1N1), 1,460 influenza A (H3N2), and 569 influenza B virus samples for resistance to neuraminidase inhibitors, which can reduce the course and intensity of the illness when applied within the first several days after onset. While almost 100% of the tested virus samples were affected by the antiviral drugs Tamiflu (oseltamivir) and Relenza (zanamivir), two 2009 H1N1 viruses and one influenza A (H3N2) virus showed resistance to Tamiflu. The latter virus was reported during the past weekend is the first resistant H3N2 to be reported this season.
Based in Chicago, Sandy Dechert has been covering women's healthcare for Examiner.com since the webzine's official startup. She has followed the 2012-2013 influenza epidemic since its inception. Sandy has also reported on the fungal meningitis outbreaks, other top women's health stories of 2012, and the creation and progress of the Affordable Care Act of 2010.
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