1. Department of Pediatrics; Federal University of Minas Gerais, Medical School; Belo Horizonte Brazil
2. Child Health Division, Belo Horizonte Municipal Health Authority; Belo Horizonte Brazil
3. Department of Pediatrics; Federal University of Health Sciences of Porto Alegre; Porto Alegre Brazil
4. Epidemiology and Diseases Control Division, Public Health System Central Laboratory; Ezequiel Dias Foundation; Belo Horizonte Brazil