China has one of the highest rates of
hepatitis B virus (HBV) endemicity in the
world. In a survey of five provinces, the
overall HBV infection rate in the general
population was found to be 42.6%, with
10.3% testing positive for hepatitis B surface
antigen (HBsAg). Higher rates were
found in rural than in urban areas. The
prevalence of HBsAg among children
under 1 year of age is quite low but
increases rapidly thereafter, reaching a
peak among 5 to 9 year olds. The pattern of
age distribution suggests that horizontal
transmission is an important route ofHBV
infection during early childhood, and the
proportion of chronic HBsAg carriage
attributable to perinatal transmission has
been estimated at only 13-20%. Contact
with infected family members probably
accounts for much of the horizontal transmission
in children. In a nationwide survey,
27.2% of families were found to have
one or more HBsAg positive members and
a strong tendency for family clustering has
been identified. The strategy for prevention
ofHBV infection includes vaccination
ofall newborns, whether their mothers are
HBsAg positive or negative, together with
vaccination of high risk populations, and
improved control measures in clinics and
blood transfusion centres.