Influenza A (H3N2) Variant Virus-Related Hospitalizations—Ohio, 2012

Since Jul 2012, 305 cases of infection with influenza A (H3N2) variant (H3N2v) virus containing the influenza A (H1N1)pdm09 M gene have occurred in multiple US states, primarily associated with swine exposure at agricultural fairs. In Ohio, from Jul 28 to Sep 25, 2012, a total of 106 confirmed H3N2v cases were identified through enhanced surveillance. Whereas most H3N2v patients experienced mild, self-limited influenza-like illness, 11 of the Ohio patients were hospitalized, representing 69% of all H3N2v hospitalizations in the US. Of these hospitalized H3N2v patients, six were at increased risk for influenza complications because of age or underlying medical conditions, including the only H3N2v-associated fatality reported in the US to date. Among other things, a CDC editorial note is included.