1. 1Department of Preventive Medicine, School of Public Health, Addis Ababa University, Addis Ababa, Ethiopia.
2. 2Institute for Medical Epidemiology, Biometrics and Informatics, Martin-Luther-University, Halle-Wittenberg, Germany.
3. 3Department of Microbiology, Immunology and Parasitology, School of Medicine, Addis Ababa University, Ethiopia.
4. 4Pathfinder International, Ethiopia.
5. 5Department of Gynecology, School of Medicine, Addis Ababa University, Addis Ababa, Ethiopia.
6. 6Department of Intramural Research, American Cancer Society, Atlanta, Georgia.
7. 7Clinic for Gynecology, Charité-Universitätmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität Berlin and Berlin Institute of Health, Berlin, Germany.
8. 8Department of Gynecology, Martin-Luther-University, Halle-Wittenberg, Germany.