[1] Minist Hlth, Singapore, Singapore
[2] Natl Univ Singapore, Saw Swee Hock Sch Publ Hlth, Singapore, Singapore
[3] Univ Edinburgh, Usher Inst Populat Hlth Sci, Ctr Global Hlth Res, Edinburgh, Midlothian, Scotland
[4] Natl Inst Communicable Dis, Div Natl Lab Serv, Ctr Resp Dis & Meningitis, Johannesburg, South Africa
[5] Univ Witwatersrand, Wits Sch Publ Hlth, Johannesburg, South Africa
[6] WHO, Global Influenza Programme, Geneva, Switzerland
[7] Univ Valle Guatemala, Res Inst, Ctr Hlth Studies, Guatemala City, Guatemala
[8] All India Inst Med Sci, Ctr Community Med, New Delhi, India
[9] Ctr Dis Control & Prevent, Influenza Div, Atlanta, GA USA