1 Department of Medicine, Columbia University Medical Center, 177 Fort Washington Avenue, Milstein Hospital Building, 6C-12, New York, NY, USA. [email protected].
2 Uganda Virus Research Institute, National Influenza Center, Entebbe, Uganda.
3 Division of Pulmonary, Allergy, and Critical Care Medicine, Columbia University Medical Center, New York, NY, USA.
4 Department of Epidemiology, Columbia University Mailman School of Public Health, New York, NY, USA.