1. Faculty of Health Sciences, Stavanger University, 4036 Stavanger, Norway
2. Stavanger University Hospital, 4068 Stavanger, Norway
3. Department of Paediatrics, Muhimbili National Hospital, Dar es Salaam 65000, Tanzania
4. Research Center, Haydom Lutheran Hospital, Haydom P.O. Box 9000, Tanzania
5. Department of Pediatrics, Weill Cornell Medical College, New York, NY 10065, USA