1. Department of Family and Community Health, University of Pennsylvania School of Nursing, Philadelphia, Pennsylvania, USA.
2. Department of Behavioral and Community Health Sciences, University of Pittsburgh School of Public Health, Pittsburgh, Pennsylvania, USA.
3. Department of Infectious Diseases, Georgetown University Medical Center, Washington, District of Columbia, USA.
4. Brookdale Center for Healthy Aging, Hunter College, City University of New York, New York City, New York, USA.
5. Department of Epidemiology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland, USA.
6. Department of Epidemiology and Infectious Diseases, University of California, Los Angeles Fielding School of Public Health, Los Angeles, California, USA.
7. Department of Infectious Diseases, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA.
8. Department of Infectious Diseases and Microbiology, University of Pittsburgh School of Public Health, Pittsburgh, Pennsylvania, USA.