Influenza A(H1N1)pdm09 mortality and hospitalization rates were also similar to those of seasonal influenza [11, 12, 13] . Influenza A(H1N1)pdm09 mortality was similar to Argentina's seasonal influenza mortality estimated using pneumonia and influenza diagnostic codes and Serfling models (2.3-10.6/100,000 person-years during 2002-2009) [9] and auto-regressive integrated moving averages models (0-4.6/100,000py during 1992-2002) [11, 12] . Our findings, therefore, suggest that early case-fatality proportions overestimated the actual burden of influenza A(H1N1)pdm09. Plausible explanations for this early overestimation include clinicians' preferentially identifying, sampling, and reporting severely ill case-patients. Nevertheless, it is important to note that while the overall influenza rates may be have been similar during 2009 and previous years, the years to life lost were likely greater during the pandemic because a greater proportion of ill persons were aged ,65 years than during a typical influenza season.