Introduction. The widespread of hepatitis B virus is a severe global public problem, and the infant hepatitis B vaccine has been proved effective. But the failure of the immune response was reported in studies, and boosters were recommended. There were few studies about the effect of hepatitis B vaccine boosters in different levels of the epidemic area.Hypothesis. Booster immunization is recommended because there may be a lack of immunization in infants vaccinated with the hepatitis B vaccine. In order to verify the effectiveness of booster immunization, this study hypothesized that it worked well in different levels of endemic areas.Aim. To evaluate the effects of hepatitis B vaccine boosters on children from the areas with different prevalence of hepatitis B whose hepatitis B surface antibody (anti-HBs) were negative (<10 mIU ml-1).Methodology. A total of 940 children were initially enrolled in screening; however, 421 were excluded. The participants were divided into three groups according to the different areas they come from: group I, low epidemic area; group II, middle epidemic area; and group III, high epidemic area. In total, 519 subjects were administered three doses of booster hepatitis B vaccine (0-1-6 months, 10 µg). The antibody titre changes were examined at four time points: 1 month after dose 1, 1 month, 1 year and 5 years after dose 3.Results. The protective seroconversion rates in three groups were 96.30, 97.16, 96.63% at 1 month after dose 1, and 100.00, 100.00, 100.00% at 1 month after dose 3, and 97.79, 100.00, 98.50% at 1 year after dose 3, and 90.77, 93.67, 93.59% at 5 years after dose 3 (P>0.05).Conclusions. This study demonstrates that three doses of booster vaccination have a longtime effect, no matter whether it is in low, middle or high prevalence areas in which subjects live.
Keywords: Hepatitis B virus (HBV); booster vaccination; effect evaluation; epidemic level; vaccine.