title: Chronic hepatitis B prevalence among children and mothers: results from a nationwide, population-based survey in Lao People's Democratic Republic.
abstract: BACKGROUND
  Hepatitis B is regarded as a serious public health issue in Lao People's Democratic Republic (Lao PDR), a Southeast Asian country. However, disease epidemiology among the general population is not well known, and thus a nationwide cross-sectional survey for hepatitis B surface antigen (HBsAg) prevalence in children and their mothers was conducted.
  
  
  RESULTS
  We applied three-stage cluster sampling using probability proportionate to size. After randomly selecting child (5 to 9 years old) and mother (15 to 45 years old) pairs from the selected villages, questionnaires and HBsAg rapid tests were conducted. Data from 965 child and mother pairs were analyzed. Multivariate logistic regression analyses were used to investigate the independent association of individual background characteristics for the odds of being HBsAg positive. In total, 17 children and 27 mothers were HBsAg positive. HBsAg prevalence was estimated to be 1.7% (95% confidence interval: 0.8%-2.6%) in children, and 2.9% (95% confidence interval: 1.7%-4.2%) in their mothers after taking sampling design and weight of each sample into account. Mother's infection status was positively associated with HBsAg positivity in children (p<0.001), whereas other potential risk factors, such as ethnicity, proximity to health centers, and history of surgery, were not. There were no significant associations between mother's HBsAg status and history of surgery, and other sociodemographic factors.
  
  
  CONCLUSIONS
  Despite the slow implementation of the hepatitis B vaccination program, HBsAg prevalence among children and their mothers was not high in Lao PDR compared to reports from neighboring countries. The reasons for the differences in prevalence among these countries are unclear. We recommend that prevalence surveys be conducted in populations born before and after the implementation of a hepatitis B vaccination program to better understand the epidemiology of hepatitis B.
authors.affiliation: National Immunization Program, Ministry of Health, Lao PDR, Simeuang Road, Vientiane, Lao PDR.
authors.forename: Anonh
authors.initials: A
authors.lastname: Xeuatvongsa
authors.affiliation: Bureau of International Cooperation, National Center for Global Health and Medicine, Shinjuku, Tokyo, Japan.
authors.forename: Kenichi
authors.initials: K
authors.lastname: Komada
authors.affiliation: Bureau of International Cooperation, National Center for Global Health and Medicine, Shinjuku, Tokyo, Japan.
authors.forename: Tomomi
authors.initials: T
authors.lastname: Kitamura
authors.affiliation: National Center for Laboratory and Epidemiology, Ministry of Health, Lao PDR, Simeuang Road, Vientiane, Lao PDR.
authors.forename: Phengta
authors.initials: P
authors.lastname: Vongphrachanh
authors.affiliation: National Immunization Program, Ministry of Health, Lao PDR, Simeuang Road, Vientiane, Lao PDR.
authors.forename: Chansay
authors.initials: C
authors.lastname: Pathammavong
authors.affiliation: National Immunization Program, Ministry of Health, Lao PDR, Simeuang Road, Vientiane, Lao PDR.
authors.forename: Kongxay
authors.initials: K
authors.lastname: Phounphenghak
authors.affiliation: National Center for Laboratory and Epidemiology, Ministry of Health, Lao PDR, Simeuang Road, Vientiane, Lao PDR.
authors.forename: Thongchanh
authors.initials: T
authors.lastname: Sisouk
authors.affiliation: National Center for Laboratory and Epidemiology, Ministry of Health, Lao PDR, Simeuang Road, Vientiane, Lao PDR.
authors.forename: Darouny
authors.initials: D
authors.lastname: Phonekeo
authors.affiliation: National Center for Laboratory and Epidemiology, Ministry of Health, Lao PDR, Simeuang Road, Vientiane, Lao PDR.
authors.forename: Bounthanom
authors.initials: B
authors.lastname: Sengkeopaseuth
authors.affiliation: National Center for Laboratory and Epidemiology, Ministry of Health, Lao PDR, Simeuang Road, Vientiane, Lao PDR.
authors.forename: Vilasak
authors.initials: V
authors.lastname: Som-Oulay
authors.affiliation: Department of Virology II, National Institute of Infectious Diseases, Musashi-murayama, Tokyo, Japan.
authors.forename: Koji
authors.initials: K
authors.lastname: Ishii
authors.affiliation: Department of Virology II, National Institute of Infectious Diseases, Musashi-murayama, Tokyo, Japan.
authors.forename: Takaji
authors.initials: T
authors.lastname: Wakita
authors.affiliation: Hepatology Research Center, National Center for Global Health and Medicine, Ichikawa, Chiba, Japan.
authors.forename: Masaya
authors.initials: M
authors.lastname: Sugiyama
authors.affiliation: Bureau of International Cooperation, National Center for Global Health and Medicine, Shinjuku, Tokyo, Japan.
authors.forename: Masahiko
authors.initials: M
authors.lastname: Hachiya
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D003430:Cross-Sectional Studies; D005260:Female; D006514:Hepatitis B Surface Antigens / Q000378:metabolism; D017325:Hepatitis B Vaccines / Q000627:therapeutic use; D019694:Hepatitis B, Chronic / Q000453:epidemiology* / Q000378:metabolism / Q000517:prevention & control; D006801:Humans; D007812:Laos; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D009035:Mothers / Q000706:statistics & numerical data; D011795:Surveys and Questionnaires; D055815:Young Adult
chemical_list: D006514:Hepatitis B Surface Antigens; D017325:Hepatitis B Vaccines