The overall flu picture didn’t change much last week, with activity remaining elevated and the H3N2 virus pushing the 2009 H1N1 strain out of its dominant spot in several parts of the country, the US Centers for Disease Control and Prevention (CDC) said today in its weekly update.
Overall, severity markers such as hospitalizations and deaths continue increase, as they typically do later in the flu season, but the levels are substantially lower than last season, which was severe.
Lab indicator details
The percentage of respiratory specimens that tested positive for flu slightly increased last week, from 25.9% to 26.1%, but clinic visits for flulike illness dropped a bit, from 5% to 4.7%, but remained well above the national baseline of 2.2%.
For the second week in a row, H3N2 viruses were reported more frequently than 2009 H1N1, which had been predominant across the season.
So far, little influenza B is circulating. At clinical labs last week, influenza A accounted 97.2% of specimens that were positive for flu. And at public health labs, of subtyped influenza A viruses last week, 62% were H3N2 and 38% were 2009 H1N1.
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