Bacterial co-infection, though uncommonly reported in the early stages of the 2009 H1N1 pandemic, may be more prevalent than initially thought. A recent analysis of lung specimens from 77 fatal cases of pandemic H1N1v 2009 infection found a prevalence of concurrent bacterial pneumonia in 29% of these patients [31] . The most common coinfecting bacterial pathogens were pneumococcus, Staphylococcus aureus, and Streptococcus pyogenes, with a median duration of illness of 6 days [31] .