1. School of Nursing and Health Professions, University of San Francisco , Orange, California , USA
2. Fielding School of Public Health, University of California, Los Angeles , Los Angeles, California , USA
3. Department of Statistics and Data Science, University of California, Los Angeles , Los Angeles, California , USA
4. School of Epidemiology and Public Health, University of Ottawa , Ottawa, Ontario , Canada
5. CHEO Research Institute , Ottawa, Ontario , Canada
6. World Health Organization Collaborating Centre for Reference and Research on Influenza , Melbourne, Victoria , Australia