CDC: pH1N1 severely affected young, middle-aged adults this flu season

Influenza A(H1N1)pdm09 virus infection has caused severe respiratory illness among young and middle-aged adults so far this season, the CDC reported.

From November to December, there have been multiple pH1N1-associated hospitalizations and many required ICU admission. There have also been fatalities reported, according to a CDC Health Advisory.

“While it’s not possible to predict which influenza viruses will predominate during the entire 2013-14 influenza season, pH1N1 has been the predominant circulating virus so far,” CDC wrote in the advisory. “For the 2013-14 season, if pH1N1 virus continues to circulate widely, illness that disproportionately affects young and middle-aged adults will occur.”

The pH1N1 virus emerged in 2009 resulted in severe illness across all age groups, but caused more illness in children and young adults, compared to older adults, according to CDC. CDC has not detected any significant changes in pH1N1 viruses that suggest increased virulence or transmissibility, but they are continuing to monitor changes in the virus, as well as morbidity and mortality surveillance.

As always, CDC recommends annual influenza vaccination for everyone aged 6 months and older and urges people who have not yet received the vaccination this season to get it now. In addition, treatment with antiviral drugs, including oseltamivir (Tamiflu, Genentech) or zanamivir (Relenza, GlaxoSmithKline), is recommended as early as possible for any patient with confirmed or suspected influenza.