1. Department of Geriatrics, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Mexico City, Mexico.
2. Inserm, Bordeaux Population Health Research Center, University of Bordeaux, Bordeaux, France.
3. Instituto Nacional de Geriatría, Mexico City, Mexico.
4. Department de Infectious Diseases, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Mexico City, Mexico.
5. Division of Infectious Diseases and Geriatric Medicine, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA.