A novel influenza A (H1N1) virus was discovered in Mexico in early 2009 (1). Infections from this strain led to declaration of a pandemic midyear, with about 61 million patients and 13,000 deaths reported by the US Centers for Disease Control (2). Although the pandemic officially ended in August 2010 (3), vaccines are still in demand to protect people against the H1N1 strain that is now expected to circulate seasonally for years to come. To best respond to…