To delay or prevent infl uenza entry at borders, infl uenza screening needs to be considerably more effective than the mostly passive program described here. We hope that during this interepidemic period, a major international review of the role of international air travel in the dissemination of emerging infectious diseases will be conducted to identify effective interventions. Such a review should consider systemwide approaches, including exit screening, standardized health declarations, active screening of individual passengers (including use of rapid laboratory tests and thermal scanning), passenger tracking, policies and practices that support sick travelers wishing to defer travel, and circumstances where airline travel should be suspended entirely. Immunologic Changes during Pandemic (H1N1) 2009, China We analyzed changes in immunologic values over time for 28 hospitalized patients with pandemic (H1N1) 2009. Levels of interleukin-6, interferon-γ, and interleukin-10 increased 1 day after illness onset and then decreased to baseline levels. Levels of virus-specific antibody were undetectable 1 day after illness onset and peaked 36 days later. mm 3 in 9 (32.1%) of 28 patients and represented <55% of total lymphocyte counts in 4 (14.3%) patients (Table). CD4 T-lymphocyte counts were <400 cells/mm 3 in 13 (46.4%) patients and represented <31% of total lymphocyte counts in 8 (28.6%) patients. CD8 T-lymphocyte counts were <190 cells/mm 3 in 3 (10.7%) patients. B-cell counts were <90 cells/mm 3 in 1 (3.6%) patient. Natural killer cells represented >27% of lymphocyte counts in 4 (14.3%) patients. Fourteen (50.0%) patients had a CD4:CD8 ratio less than the standard reference ratio of 1.4.