1 Epicentre, Yaoundé BP 12069, Cameroon; Faculty of Medicine and Biomedical Research, University of Yaoundé 1, Joseph Tchooungui Akoa, Yaoundé, Cameroon. Electronic address: yap.boum@epicentre.msf.org.
2 Faculty of Medicine and Biomedical Research, University of Yaoundé 1, Joseph Tchooungui Akoa, Yaoundé, Cameroon.
3 Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA.