Influenza that fickle fellow

While influenza epidemics occur annually the variation in the timing, peak and magnitude remain a mystery. So far influenza in NYC has been mild. Several surveillance systems are used to gauge the severity of flu season and by any of them either flu hasn’t arrived yet or the strain has not varied much from last season. Outpatient visits for influenza-like illness in NYC are still below the 2.5% threshold and of nearly 1800 lab tests done for flu in the first week of 2012 less than 20 were positive (during peak flu season this can range as high as 15%). Elsewhere in the country the story is much the same with only a few states showing activity, but no hot regions.  Most of the circulating strains are the H3-type with smaller proportions of H1 and B; all components of this year’s vaccine. Looking at the world picture there is activity in Northern Africa and Japan, however, in general activity remains low.

It is still a good idea to get a flu shot, especially if you have a chronic illness. 

http://gis.cdc.gov/grasp/fluview/main.html

Swine Flu update

The CDC has learned of two cases of swine origin influenza A of the H3N2 strain in Minnesota and West Virginia. The WV case appears to have occurred in a young child and local health officials, in conjunction with the CDC, are investigating and testing other ill children. Those kids could have routine seasonal viruses, like RSV, another flu strain or the newest swine-origin flu to cross over to humans. Disease with this strain continues to be mild.

In NYC there isn't much flu around to speak of and all surveillance systems are at or below baseline. Stay tuned.

http://www.cdc.gov/flu/weekly/

http://www.cdc.gov/media/haveyouheard/stories/novel_influenza.html

http://www.dhhr.wv.gov/oeps/disease/flu/Pages/fluSurveillance.aspx