Hepatitis B virus in the Lao People's Democratic Republic: A cross sectional serosurvey in different cohorts

Antony P. Black, Phonethipsavanh Nouanthong, Naphavan Nanthavong, Chanthasone Souvannaso, Keooudomphone Vilivong, Prapan Jutavijittum, Bounthome Samountry, Nina Lütteke, Judith M. Hübschen, Sylvie Goossens, Fabrice Quet, Yves Buisson, Claude P. Muller*

*Corresponding author for this work

Research output: Contribution to journalArticleResearchpeer-review

33 Citations (Scopus)

Abstract

Background: Despite hepatitis B vaccination at birth and at 6, 10 and 14 weeks of age, hepatitis B virus (HBV) infection continues to be endemic in the Lao People's Democratic Republic (PDR). We carried out a cross-sectional serological study in infants, pre-school children, school pupils and pregnant women to determine their burden of disease, risk of infection and vaccination status. Methods: A total of 2471 participants between 9 months and 46 years old were recruited from urban (Vientiane Capital, Luang Prabang), semi-urban (Boulhikhamxai and Savannakhet) and remote rural areas (Huaphan). All sera were tested for anti-HBs and anti-HBc. Sera testing positive for anti-HBc alone were further tested for the presence of HBsAg. Results: A low prevalence of HBsAg (0.5%) was detected among infants from Vientiane and Luang Prabang, indicating some success of the vaccination policy. However, only 65.6% had protective anti-HBs antibodies, suggesting that vaccination coverage or responses remain sub-optimal, even in these urban populations. In pre-school children from remote areas in Huaphan, 21.2% were positive for anti-HBc antibodies, and 4.6% were for HBsAg positive, showing that a significant proportion of children in these rural regions have early exposure to HBV. In pre-school children with 3 documented HBV vaccinations, only 17.0% (15/55) were serologically protected. Among school-children from semi-urban regions of Luang Prabang, Boulhikhamxai and Savannakhet provinces, those below the age of 9 who were born after HBV vaccine introduction had anti-HBc and HBsAg prevalence of 11.7% and 4.1%, respectively. The prevalence increased to 19.4% and 7.8% of 10-14 year olds and to 27% and 10.2% of 15-19 year olds. Pregnant women from Luang Prabang and Vientiane had very high anti-HBc and HBsAg prevalence (49.5% and 8.2%), indicating high exposure and risk of onward vertical transmission to the unborn infant. Conclusions: Overall, the results demonstrate a dramatic deficiency in vaccination coverage and vaccine responses and/or documentation within the regions of Lao PDR studied, which included urbanized areas with better health care access. Timely and effective hepatitis B vaccination coverage is needed in Lao PDR.

Original languageEnglish
Article number457
JournalBMC Infectious Diseases
Volume14
Issue number1
DOIs
Publication statusPublished - 2014

Keywords

  • Cross-sectional
  • Hepatitis B virus
  • Serology
  • Vaccine

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