DDX41 and influenza: In contrast to the differences observed at entry into the study (time point A), no differences were observed in IFN-γ production between study participants with or without previous seasonal flu vaccinations (Table 1) at time point C. At this time point, levels of A/H1N1/California/7/2009-specific Abs were below protective levels (SRH < 25 mm2) in both vaccinated and unvaccinated participants.