Hepatitis A virus in Lao People’s Democratic Republic: Seroprevalence and risk factors

Vilaysone Khounvisith, Xaipasong Xaiyaphet, Phetsavanh Chanthavilay, Phonethipsavanh Nouanthong, Bounta Vongphachanh, Daniel Reinharz, Claude P. Muller, Antony P. Black*

*Corresponding author for this work

Research output: Contribution to journalArticleResearchpeer-review

2 Citations (Scopus)


Despite several recent reports of outbreaks of hepatitis A, little is known about the disease burden in Lao People’s Democratic Republic (PDR). We conducted a cross-sectional age-stratified seroprevalence study of anti–hepatitis A virus (HAV) IgG and risk factors in a rural province (Xiengkhouang) and Vientiane capital in Lao PDR. Overall, 62% of participants were anti-HAV positive in Xiengkhouang Province compared with 45.5% in Vientiane capital. In Xiengkhouang, 23.7% of 5-to 10-year-olds were already seropositive compared with 5% in Vientiane. A dramatic increase in seroprevalence occurred between 15-to 20-year and 21-to 30-year age-groups (35.7–62.4%, Xiengkhouang, and 11.5–69.7%, Vientiane) until essentially all older adults were positive in both locations. The main risk factors for HAV antibodies were age, non–Lao-Tai ethnicity, and food-related risk factors. In conclusion, Lao children seem to be exposed very early to HAV, particularly in rural settings, and exposure continues throughout their lives, mostly without being reported. In the older birth cohorts, the high seroprevalence may largely reflect poor sanitation and exposure during childhood. In Vientiane capital, the lower seroprevalence at young ages may reflect better water sanitation since the late 1990s. A comparison with neighboring Thailand indicates that the impact of improved sanitation in Lao PDR began only two decades later. Further improvements in water sanitation, in particular in the rural districts, and better food hygiene are warranted. Our study also suggests that HAV infections are underreported. Improved reporting would provide guidance for targeted interventions to further reduce HAV infections.

Original languageEnglish
Pages (from-to)164-168
Number of pages5
JournalAmerican Journal of Tropical Medicine and Hygiene
Issue number1
Publication statusPublished - Jul 2020


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