1. Department of Internal Medicine, School of Medicine, Hamadan University of Medical Sciences, Hamadan, Iran
2. Department of Medical Virology, Faculty of Medicine, Hamadan University of Medical Sciences, Hamadan, Iran
3. Department of Biostatistics, School of Public Health, Hamadan University of Medical Sciences, Hamadan, Iran
4. Clinical Research Development Unit of Shahid Beheshti Hospital, Hamadan University of Medical Sciences, Hamadan, Iran