1 Infectious Diseases Section and Research Unit, Hospital Universitario Fundación Alcorcón, 28922 Alcorcón, Madrid, Spain. Electronic address: mvelasco@fhalcorcon.es.
2 Internal Medicine Unit, Hospital Universitario Fundación Alcorcón, 28922 Alcorcón, Madrid, Spain; Department of Medical Specialities and Public Health, Rey Juan Carlos University, Alcorcón, Madrid, Spain.