During 6 weeks when there was co-circulation of pandemic and seasonal influenza A viruses in the community, hospital staff triaged more than eighteen-hundred patients with respiratory complaints and identified 12% for inpatient care. The triage system was based on assumptions about who is at risk for developing complications from seasonal influenza (e.g. patients aged over 65 years). Our analyses, however, suggested that patients infected with 2009 pandemic influenza A (H1N1) tended to be younger than seasonal influenza A patients. Nevertheless, our data suggest that clinicians used the ILI-score to help them determine, with minimal misclassification, which patients needed hospitalization versus who could be managed as outpatients [18] . The ILI-score helped guide clinicians to decide who needed hospital care and antiviral treatment when timely laboratory confirmation of influenza was not available. Only 1% of patients triaged needed re-evaluation. Such a system could be readily used to efficiently triage patients during outbreaks and epidemics by adapting the system's scores to match the anticipated characteristics of patients who are at highest risk of developing complications. While the triaging system led clinicians to hospitalize traditional groups at risk for complications from seasonal influenza (i.e. those with chronic medical illnesses), patients infected with 2009 pandemic influenza A (H1N1) were often young and had few pre-existing conditions [20] . These data are comparable with Mexican Directorate General of Epidemiology data that suggest 56% of pandemic (H1N1) confirmed deaths occurred among those aged 30-59 years, many of whom were previously healthy [21] . The age shift in 2009 pandemic influenza A (H1N1) cases may be caused by cross-reactive immunity from prior influenza infections in 33% of those aged more than 60 years [22, 23] . Health officials should adjust pandemic triaging tools to account for the younger age distribution of cases [24] . Pregnancy should also be included as a risk factor in triaging tools. Although there were too few pregnant women in our case series for subgroup analyses, other data suggest pregnant women are at high risk of developing severe complications from 2009 pandemic influenza A (H1N1) [25] .