Hepatitis A virus antibody in mentally retarded children.

Hepatitis A virus is an important public health problem especially in areas where hygiene and sanitation are improving such as Southeast Asia because, while the total number of cases of hepatitis A infection are reduced, the number of symptomatic and severe cases increase. The antibody prevalence in Bangkok and in rural areas of Thailand has markedly declined among children and adolescents (Poovorawan et al, 1991; 1994). The transition from high to low endemicity poses the danger of outbreaks of symptomatic hepatitis A infection especially among high risk groups such as school children, factory workers, and institutions for the mentally retarded.