[1] Univ Bergen, Ctr Int Hlth, N-5021 Bergen, Norway
[2] Univ Bergen, Inst Med, N-5021 Bergen, Norway
[3] Haukeland Hosp, N-5021 Bergen, Norway
[4] Muhimbili Univ, Coll Hlth Sci, Dept Paediat & Child Hlth, Dar Es Salaam, Tanzania
[5] Muhimbili Univ, Coll Hlth Sci, Dept Microbiol & Immunol, Dar Es Salaam, Tanzania