Data from 2010-2014 was available at WHO database. After 2014, data was only published through monthly situation updates by WHO Western Pacific Office. Those updates reported cases until December each year, except for 2015 and 2016 in Vietnam, where only cases until November was available. Data for Lao PDR was missing for 2013 and 2014 as well as data for Cambodia for 2016. Data for 2019 represents cases until October for Vietnam and until November (week 41) for Lao PDR and Cambodia.