[1] Univ New S Wales, Fac Med, Sch Publ Hlth & Community Med, Sydney, NSW 2052, Australia
[2] Univ Western Australia, Ctr Child Hlth Res, Telethon Inst Child Hlth Res, Perth, WA 6009, Australia
[3] Minist Publ Hlth, Dept Dis Control, Bur Epidemiol, Bangkok, Thailand
[4] Khon Kaen Univ, Fac Nursing, Res & Training Ctr Enhancing Qual Life Working Ag, Khon Kaen, Thailand
[5] Childrens Hosp, Natl Ctr Immunisat Res & Surveillance Vaccine Pre, Westmead, NSW, Australia
[6] Univ Sydney, Discipline Paediat & Child Hlth, Sydney, NSW 2006, Australia