371 households will be randomly selected from each site in Bangladesh, Cambodia, Myanmar, and Thailand. Assuming each household has an average of 4.5 members and all members will be sampled, 1500 participants will be recruited per site. This sample size allows for the overall prevalence estimation of key survey indicators with 95% confidence and 5% degree of precision.~The survey components include questionnaire interview, physical examination, blood sample collection, and point of care (PoC) tests. The questionnaire interview will collect information on household characteristics, members' disability, presence or history of disease, risk factors, self-perceived quality of life, and health seeking behaviour. For women, questions about reproductive health and antenatal care, and for young children, vaccination coverage and achievement of child development goals, will also be assessed.~For physical examinations, tympanic temperature, weight and height will be measured in all household members, mid-upper arm circumference in young children, and blood pressure in adults. Blood sample will be collected from all participants aged 6 months and above. Venous blood samples will be collected from participants aged 5 years and older, and dried blood spot will be collected from children under 5 years. Samples will be shipped to a central laboratory and analysed. Haemoglobin PoC will be administered to all participants.~All data will be collected directly on an electronic case report form using tablets, and uploaded to an electronic database.
A cross-sectional household survey with two-stage cluster-randomized sampling. This cross-sectional household survey design to recruit a random sample of households that is representative for each of the study sites. From the selected households, all consenting, household members will be included in the study.~This study is funded by the UK Wellcome Trust. The grant reference number is 215604/Z/19/Z