Affiliation: | 1. Department of Family Medicine, Medical University of Warsaw, 1a Banacha Str., 02-097 Warsaw, Poland;2. Department of Epidemiology and Tropical Medicine, Military Institute of Medicine, 4 Grudzinskiego Str., 81-103 Gdynia, Poland;3. Department of Paediatric Infectious Diseases, Medical University, 44 Bujwida Str., 50-345 Wroclaw, Poland |