Chronic hepatitis B virus (HBV) infection causes approximately 325,000 deaths from cirrhosis and liver cancer each year in the Western Pacific Region of the World Health Organization (WHO). With an estimated infection prevalence of >8%, HBV is considered highly endemic in Laos and is most commonly transmitted from mother to child during birth and early childhood. A hepatitis B vaccine birth dose (HepB-BD) is needed to prevent mother-to-child HBV transmission. To assess gaps in coverage and identify possible remedies for improvement of coverage, during the 3-month period December 2011-February 2012, the Laos Ministry of Health and WHO staff members surveyed 37 health facilities in five provinces in Laos, inquiring about HepB-BD knowledge and practices among health-care providers and estimating HepB-BD coverage provided by the facilities. For facility-based births, the median HepB-BD coverage was 74% (interquartile range: 39%-97%). Hepatitis B vaccine was not in stock at 18 (49%) of the 37 facilities on the day they were visited. Of the 37 facilities, 17 (46%) assisted with home births, and 23 (62%) conducted postnatal home visits. Of the 17 facilities that assisted with home births, seven (41%) included HepB-BD vaccination as part of the service; of the 23 that conducted postnatal home visits, 15 (65%) provided HepB-BD as part of the visit. However, among those reporting that they provided these outreach services, only 48 births were recorded as attended, and only 81 postnatal visits were recorded as conducted during the 3-month period. Health facilities can help prevent mother-to-child HBV transmission in Laos by ensuring vaccine availability, vaccinating all infants born in the facility, and enhancing outreach services for home births.
[Show abstract][Hide abstract] ABSTRACT: 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.
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.
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.
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.
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